Entomology

Introduction Entomology (entomon: insect, logos: study) is a branch of zoology in which the morphology, physiology and the biological aspects of insects are studied. In the animal kingdom more than 1 million species of animals have been described. So far of them arthropods constitute about 80%. About 9 million species of insects have been identified and described till date. The insect does form about 80% of the total arthropod population. The insects evolved from annelid like ancestors. During the Oligocene period, since then they have been diversified and dominant forms inhabiting almost all habitats even including the ocean. For example, Halobates the (water strides) is found on the sea surface several kilometers away from the land. Insects generally inhabit every conceivable habitat from the cold Polar Regions to the hot tropicals. Tey are free living, parasitic, phytophagus, and predators and so on. The larvae of Psilopa petroli (dipteran fly) live in the pools of crude petroleum in California. The insect does inhabit every inhospitable medium. The insects have been man’s chief competitors on earth. Their wonderful adaptations have made them a serious threat to human existence, because to the insect feeds on his crops and many of his essential things. The reason for their success on the earth and dominance over the other animals are the following: 1. Among the invertebrates the insects are gifted with flight. Their capacity for flight enables them to move quickly from one place to another place for breeding and feeding. 2. Like birds the insects exhibit migration. They migrate in mass to distant places in search of food. 3. since the insects have the ability of flight they can easily escape from their enemies. 4. their exoskeleton is well developed adapted to live even on the dry land environment. 5. they feed on different kinds of food (polyphagous) and their mouth parts are well suited for different modes of living. 6. the fecundity of insects is highly remarkable. Generally insects with short life cycles produce more eggs. For example, Jeuya purchase (cottony cushion / fecundity scale) 200 to 1400 eggs at a time. The eggs of most of the insects are well protected and they can withstand the extremes of environment conditions, the phenomenon Parthenogenesis is also quite common among the insects. 7. the insects are economically important animals as they are destructive to crops, grains, stored products and so on. Some of the insects are responsible for transmitting pathogenic organisms, causing serious disease such as malaria, yellow fever, filariasis in man. The domestic animals are also affected by the insects. The different branches of entomology are: 1. Agricultural entomology: deals with the insect pest, their biology and control measures. 2. economic entomology: deals with the economic aspects of insects. 3. forest entomology: conserved with those insects that attack forest plants. The various measures to control the insects that destroy the forest plants are included. 4. veterinary entomology: is the study of the biology of the insect vectors and the mode of transmission of he pathogenic infection in farm animals. 5. medical entomology: is the study of biology of the insect vectors and transmitters. It also deals with control measures. 6. aquatic entomology: which deals with various aspects of aquatic insects. Insect morphology in general. The body of any insect is segmented and made up of an exoskeleton. The exoskeleton is the cuticle composed of a substance called the chitin. In each segment, there is a dorsal tergum or ventral sternum which is connected together by a pleural memberane laterally. The body can be divided into the head, thorax and the abdomen. In the adult these segments are not very distinct. The head consists of several plates, a pair of antennas, compound eyes and simple eyes (ocilli) besides the mouth.

HEAD: 1. Prognathus: the head is with the long axis of placed horizontally and hence the mouth parts are anterior in position. E.g. earwigs, Dipteran fly beetles. 2. Hypognathus: here the long axis of the head is vertical and the mouth parts are ventral in position. E.g. ants, grasshoppers and bees. 3. Opisthognathus: the head is directed backwards. The mouth parts are posterior ventral in position. E.g. cockroaches and Blatta. MOUTH PARTS: The mouth parts of cockroach are biting and chewing type. It is the basic and primitive type. The mouth parts consist of the following parts: 1. LABRUM: it is otherwise called as the upperlip. The mabrum is made up of a single broad plate attached with the jaws. It heps to store the food into the mouth. In the lower surface of the labrum, crescent shaped epipharynx is present, in which many taste buds are being present. 2. LABIUM: it is the lower lip and it consists of many pieces, the labium has a submentum and mentum. Above the mentum, lies the prementum or para glossa. In between the paraglossa small glossae are found. A four segmented labial palk arise from each side of the mentum. 3. HYPOPHARYNX (tongue): a cone like structure lies in the centre of the mouth cavity. The salivary glands open at its base through the salivary duct. 4. MANDIBLES: a pair of mandibles one in each side of the mouth. The mandibles are hard with many teeth adapted for cutting and chewing. 5. MAXILLAE: the paired maxillae are situated in the lateral side of the mouth. The maxillae consist of many segments, the cardo and stipes or the basal segments (protopodite). From the stipes arise maxillary palps (exopodite) with five joints and the inner lacinea and galea (endopodite) are found. The maxillae aid to hold the food while feeding. 6. THORAX: the thorax is 3 segmented called as the prothorax, the mesothorax and the metathorax. A small neck is found between the head and the thorax. From each thoracic segment, paired legs are found ventrally. Each leg consists of a basal coax a stout femur and a long trochanter and many joined tarsus. The legs are adapted for sartorial or jumping. Generally two pairs of wings are from the mesothorax and the other from the metathorax arise dorsally. The wings are membranous with many veins to support them. Generalized Insect Head with Chewing Type Mouthparts

Siphoning - Moths and butterflies. When feeding the proboscis is uncoiled and extended.Nectar is sucked upinto the mouth or oral cavity. The proboscis is a modified maxillae.

Sponging - Found in adults of specialized flies. During feeding the proboscis (modified labium) is lowered and salivary secretions are pumped onto the food. The dissolved or suspended food then moves by capillary action into the pseudotracheae (sponge) and is ingested. There may be sharp teeth on the pseudotracheae to rasp flesh and draw up blood. The labella is the fleshy distal end of the labium that functions as a sponge-like organ to sop up liquids.

Piercing-Sucking - Found in a variety of insects, such as herbivorous and predacious bugs and mosquitoes. Mandibles and maxillae are formed into stylets which are enclosed by the labium. Once the stylets penetrate, a secretion is injected to dissolve tissue, act as a toxin in predacious species, or as anticoagulant for mosquitoes.

Chewing-Lapping - Adult honeybees and bumble bees. Mouthparts are modified to utilize liquid food, honey and nectar. A central "tongue" is used to draw liquid into the body. The mandibles are not used for feeding but function to cut floral tissue to gain access to nectar, for defense, and for manipulating wax.

DIGESTIVE SYSTEM: the mouth leads into the buccal cavity. The buccal cavity opens into a long and narrow pesophagus. On either sides of the oesophagus, lies the salivary glands. The crop is wide and a long structure in which the food is stored. The crop leads into a wide stomach. In between the two there are many projections called the Hepatic caeae which secrete the digestive enzymes. The stomach leads into the ileum. The wall of the ileum has many long hair like projections called the malphigian tubules which are secretory in function. The ileum opens into the rectum which finally opens out through the anus.

ABDOMEN: the abdomen is slender and gradually narrowing posteriorly. It consists of 11 segments.

RESPIRATORY SYSTEM: the respiratory system consists of spiracles, tracheae and tracheoles. There are totally 10 pairs of spiracles (2 thoracic and 8 abdomen) in their lateral side. Each spiracle opens into

the trachea which branch into minute openings called tracheoles. The tracheoles are connected with the muscles. Air from the atmosphere reaches the trachea through the spiracles and through the tracheoles reaches the muscles directly.

NERVOUS SYSTEM: the nervous system includes a pair of supra oesophagus ganglion (Brain) and a sub oesophagal ganglion and connectives that connect the 2 ganglia. The supra oesophagal ganglion supply nerves to the compound eyes , ocilli and antenna. The sub oesophagal ganglion supplies nerves to the mouth parts. A ventral nerve part arise from the sub oesophagal ganglion and continues posteriorly. There are 3 large thoraces ganglia supplying nerves to the wings and the legs. 8 abdominal ganglia are also lovated in the abdomen. They supply nerves to the digestive organs, trachea, heart and the reproductive organs.

REPRODUCTIVE SYSTEM: the male consist of pair of testes which produes the sperms and the female consists of a pair of ovaries composed of ovarian follicles.

CLASSIFICATION OF INSECTS: the classification of organism is based on a hierarchy of categories. The major categories used in the animal classification of phylum, class, order, family, genus and species. The scientific names of a species are binomial and it is composed of 2 names, a genus name and a species name. The system if binomial nomenclature we use today for classification was advanced by the Swedish naturalist Carlos Linnaeus in 1758. The binomial of the first species is always printed in Italics or, if hand written is underlined to indicate italics. The name of a genera and higher categories begin with a capital letter but the specific name of the species and sub specific names always begin with a lower case letter. Brauer (1885) classified the insects under 2 major orders namely wingless insects, Apterygota and winged insects, Pterygota. He classified insects under 16 orders and at present it is the same modification of insects classification as 28 orders which was formulated by A.D. Himm. GENERAL CLASSIFICATION OF INSECTS: the classification of insects is written from the most primitive insects to the most highly evolved. Class Subclass I Order 1 Order 2 Order 3 Order 4

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Insecta Apterygota ( primitively wingless insects). Protura e.g. Proturaus Collembola e.g. springtails Diplura e.g. Diplurans. Thysanura e.g. Bristle tails.

Subclass II Division I Order 5 Order 6 Order 7 Order 8 Order 9 Order 10 Order 11 Order 12 Order 13 Order 14 Order 15 Order 16 Order 17 Order 18 Order 19

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Pterygota (winged and secondary wingless insects) Exopterygota (Hemimetabola and simple body change during growth) Ephemeroptera e.g. Mayflies. Odonata e.g. Dragon flies and Damsel flies. Orthoptera e.g. Grass hopper, cricket, cockroaches, mantids, stick insects. Dermaptera e.g. Earwigs. Isoptera e.g. termites Embioptera e.g. webspinners. Plecoptera e.g. Stoneflies. Zoraptera e.g. Zorapterans Psocoptera e.g. Psocids. Mallophaga e.g. Chewing lice Anoplura e.g. sucking lice. Thysanoptera e.g. thrips. Hemiptera e.g. bugs. Grylloblattoidea e.g. grylloblatta. Phasmida e.g. leaf stick and walking insect.

Division II Order 20

: Endopetrygota complex ( Holometabola complex, body changes during growth). : Neuroptera e.g. Alder flies, Antilions, Dobsonflies, Fishflies, Laceflies, Shakeflies, Owlflies. : Coleoptera e.g. Beetles : Strepsiptera e.g. Stylopids : Mcoptera e.g. Scorpionflies. : Trichoptera e.g. Caddisflies : Lepidoptera e.g. butterflies and moths. : Diptera e.g. Flies and mosquitoes. : Siphonoptera e.g. Fleas : Hymenoptera e.g. Ants, bees, wasps, sandflies.

Order 21 Order 22 Order 23 Order 24 Order 25 Order 26 Order 27 Order 28

SUBCLASS I Apterygota or Ametabola 1. Apterygota are an assemblage of most primitive wingless insects consisting of the order Protura, Collembola, Diptera and Thysanura. 2. The body is covered with minute scales. 3. the internal structures that strengthen the thorax for flight in winged insects are absent in these order. 4. members of this subclass with very little change in form during the development, a pattern called “no metamorphosis”. 5. insects in these orders have mouth parts housed with in a cavity and only the tips protrude when the insects are feeding. Such mouth parts are called as ectognathus. ORDER I : Protura e.g. Proturans 1. the proturans are unpigmented soft bodied small whitish insects. Usually found in conserved situation. 2. the head is prognathus with piercing and sucking type of mouth parts. 3. both compound eyes and ocilli are absent. 4. antennae are vestigial. 5. another unusual feature of Proturans is that young begin with 9 segments and add 3 more during development, a phenomenon known as Anamorphosis. 6. the final segment in the adult abdomen is a primitive structure Telson, and hence sometimes named as Telson tails.

ORDER 2 : Collembola e.g. spring tails and snow flea. 1. The members of this order are minute soft bodied, pigmented or unpigmented insects. 2. The body is covered with scales. 3. The collembolan are ancient group whose member possess a central extensible tube like structure attached to the under side of the first abdominal segment called Collophore, hence their ordinal name. 4. The collophore or ‘glue bar’ are eversible and maintain secretion at the tip. It was believed that the structure was used as a aid in climbing on smooth surfaces but no recent evidence such as it may be used in water uptake or preening. 5. Mouth parts are usually chewing type but in some species the maxillae and mandibles are modified into long sharp stylets. 6. Each eye occurs as a loose aggregation of single ommatidia. 7. Many are true soil dwelling and cave swelling forms. 8. The common name spring tail comes from the ‘furcula’ arising from the under side of the abdomen near the tip. Most of the time, the furcula is cocked by a clasp, the tenaculum. When a spring tail is disturbed, the furcula is released propelling the insect for a distance several times its body length.

ORDER 3: THYSANURA e.g. bristletails. 1. the members of this order are minute soft bodied pigmented or unpigmented insects. 2. scales cover the body and often given silver sheen. 3. the head is sessile. 4. the most distinctive feature of these insects are the two long cerci and a medium caudal filament that occur at the end of the abdomen giving appearance of 3 tails. 5. presence of compound eyes and reduced ocilli. 6. temperature requirements may vary from cooled damped situation favored by silver fish to warm dry are like furnace rooms inhabited by firebrats that do cause damage to the possession by feeding on starchy substances.

ORDER 4: DIPLURA e.g. Diplurans. 1. they are small, blind, whitish insects less than 7mm long with chewing mouth parts and with many segmented antennae. The name is derived from the 2 prominent cerci at the tip of the abdomen that occur as styli. 2. they occur in the soil and soil surface debris.

SUBCLASS II: Pterygota (metabola). 1. the important characteristic of the subclass pterygota is the possession of 2 pairs of wings in the adult stage one arising from the dorsal side of the mesothorax and the other from the metathorax. 2. some adult pterygota lack wings for e.g. fleas. 3. orders with individuals that have a simple form of body change during growth and external wing development are placed under the division exopterygota. 4. those with complex changes in body form and internal wing development are placed under the division endopterygota. 5. the intugment is well chitinized, well developed compound eyes and ocilli, distinct pupal stages, abdominal lacks and abdominal appendages. DIVISION I: Exopteryota (hemimetabola). 1. the development is incomplete without a pupal stage. 2. during development the wings are developed from the wing bud and externally, the immature stages resembles the adult and are called as the nymphs. 3. the nymphs after several instars becomes the adult. 4. some of the young ones are aquatic which are called as naiads. ODRDER 5: Ephmeroptera. E.g. mayflies. 1. they are most primitive types of winged insects and are characteristic by triangular and veined membranous wings, bristle like antennae and mouth parts not functional in adult. 2. mayflies lay eggs on the surface of the water and the young naiads remain and develop in the water by feeding on the algae and detritus. 3. an immature looks like the adult in the overall body shape but has well developed leaf like gills and 3 tails. 4. head is immovable with short antennae. 5. mouth parts are vestigial and non functional in adults, but biting and chewing in case of larvae. 6. adult may flies emerge in huge swarms over bodies of water and mate. Females lay eggs within few minutes to a few hours after mating. The adults do not feed and die within a day or two. Therefore the name ephemeroptera (short lived).

ORDER 6: ODONATA. E.g. Dragon flies and damsel flies. 1. odonates are large and brightly colored insects which are very active fliers. They are amphibiotic with a large movable head. 2. they have net veined membranous wings, protruding compound eyes, short antennae, 30 ocilli ad long slender body. 3. mouth parts are well developed with well developed mandibles. 4. adult feed on mosquitoes and midges. 5. females lay egg in water and the immature do not swim but walk along the bottom. 6. development of the adult stage requires 1-4 years.

ORDER 7: ORTHOPTERA / DICTYOPTERA. E.g. cockroaches. 1. members of this order are terrestrial insects with well developed mandibles. 2. the thorax is distinct with leathery wings in some cases, the forewings are more chitinised and are called tegmina. 3. the members of this order have well developed legs for funning and hypognathus. 4. mouth parts are typicallt chewing type and pair of cerci is present at the tip of the abdomen. 5. there is a little change in the body form during growth and development. Gradual metamorphosis. 6. sound production is very common among orthopterans, particularly among grasshoppers and cricket. Sound is made by rubbing their body parts together. This behavior is called Strigulation, usually involved in mate finding.

ORDER 8: Dermaptera. E.g. Earwigs. 1. they are small sized insects with a pair of cerci and with a hort leathery fore wing and a long membranous hind wing. 2. they have chewing type of mouth parts and show gradual metamorphosis. 3. they are nocturnal and omnivorous in habit. A gland is present near the abdomen which emits a foul smelling liquid and which serves as protection from enemies. 4. they are active at night and feed on decaying organic matter.

ORDER 9: ISOPTERA e.g. Termites. 1. they are also called as white ants and their body differs from those of ants in having a broad abdomen. 2. the mouth parts are of chewing type and show gradual metamorphosis. 3. the termite includes the kings, queens, workers and soldiers. 4. workers do the work of colony including gathering food, feeding reproductive, soldiers, young and constructing the nest etc. 5. most termites are saprophytes. 6. two pairs of similar wings are possessed by the reproductives but, shed after the mating flight. Antennar of modulate length, cerci short.

ORDER: 10 Embioptera e.g. Web spinners. 1. webspinners are small insects 4-7 mm long. Males may be winged or wingless and females have wings. 2. mouth parts are chewing types and presence of a pair of short cerci and exhibit gradual metamorphosis.

3. an unusual characteristics of Web spinners is the presence of silk glands and spinning hairs. They feed in dead plant materials, lichens and mosses.

ORDER: 11 Plecoptera. E,g, stone flies 1. they are associated with aquatic environments. 2. antennae are long and slender, tarsi are segmented. 3. mouth parts are chewing type and presence of prominent pair of cerci. 4. The name stone flies come from the habitat of the immatures which crawl under the stones on the bottom of the streams. 5. Species are predacious or even omnivorous.

ORDER:12 zoraptera. E.g. Zorapterans. 1. they superficially resemble termites. 2. adults of either sex may be winged or wingless. 3. presence of compound eyes and a pair of cerci. 4. mouth parts are chewing type and shows gradual metamorphosis. 5. found in rotten logs, under bark and piles of saw dust.

ORDER 13: Psocoptera e.g. psocids (book lice). 1. minute apterous, dimorphic, mouth parts are biting and chewing type. 2. mandibles are well developed compound eyes are large and ocilli are three in number. 3. the legs are adapted for running. 4. the book lice feed on glue of binding books and also on dead materials and plants.

ORDER 14: Mallophaga. E.g. chewing lice, bird lice 1. they are minute, flattened, apterous, cound as ecto parasites on birds and mammals. 2. mouth parts are chewing type, feeding on the scales, feathers and skin products. 3. the females is larger than the male and this order shows gradual type of metamorphosis.

ORDER: 15 Anoplura (Siphunculata) e.g. sucking lice 1. the members of this order are exclusively ecto parasites on mammals including man. 2. they are dorsoventrally flattened, wingless, piercing and sucking type of mouth parts. 3. the compound eyes are very much reduced and they are transmitters of certain bacterial disease in man.

ORDER: 16 Thysanoptera e.g. Thrips. 1. the thrips are very minute, 0.5 – 1 mm insects and most of them are pests on many crops. 2. mouth parts are grasping and sucking type situated ventrally behind the head. 3. compound eyes, ocilli are present, wings are present, but may be reduced or absent. 4. the wings are frinched, which is the characteristic feature of this order.

ORDER :17 Hemiptera e.g. Bugs, aphis, plant bugs, and scaled insects. 1. this is one of the largest order and the development is hemimetabolous. 2. when wings are present, the forewing is larger or heavier in texture than the hind wings. 3. mouth parts are of piercing and sucking type. 4. most of them in this order are important plant pest and odoriferous glands are the characteristic feature of most of the bugs. 5. some species of hemiptera are predatory on other insects unlike a few including the human bed bug are blood sucking on higher animals.

ORDER: 18 Grylloblattoidea e.g. Grylloblatta 1. they are small size and light colored insects present beneath the stones of high altitude. 2. eyes are reduced or absent. 3. moderate sized wingless insects. 4. moderately long antennae with many joints. 5. mouth parts are of biting pattern. 6. ocilli are absent and these insects are of no economic importance.

7.

ORDER: 19 Phasmida e.g. leaf insect, walking insect etc. 1. the insects are large in size and elongated and in cylindrical forms. E.g. stick insects, flattened leaf insect, winged or wingless, fore wings when present are usually small. 2. head is movable and antennae are long. 3. mouth parts are of biting and chewing type. 4. compound eyes are well developed and ocilli are absent. These insects exhibit the phenomenon of camouflage and are plant feeders.

DIVISION II: Endopterygota (Holometabola, insects of these division are advanced). These forms have the following characteristic features: 1. metamorphosis is complete with a distinct pupal stage. 2. during the development, the wings develop internal from the wing buds. 3. a distinct larval stage is found. The larvae are quite different from the adult in their morphology, habit and habitat. 4. in certain cases, more larval stages and a little change from the normal metamorphosis pattern is exhibited which can be termed as hyper metamorphosis. ORDER: 20 e.g. Neuroptera e.g, Alder flies, Dobson flies, owl flies, fish flies, lace flies, antlions, snake flies. 1. mouth parts are of biting and chewing type. 2. compound eyes are large, ocilli are absent or rarely present. 3. moderate sized, soft bodied wit h 2 pairs of large wings, numerous veins and cross veins. 4. antennae are rather long and thread like. 5. all species are predatory. 6. Antlions are predatory insects, feeding on coccids, aphids and mites.

ORDER: 21 Coleoptera e.g. beetles. 1. these are phytophagous, carnivores and predacious in their habit. 2. mouth parts are of biting and chewing type. 3. metamorphosis is complete and the larvae are generally called as grubs. 4. larvae variable in form, legless in some group. 5. compound eyes are well developed but ocilli are absent.

6. all beetles have a strongly developed hard exo skeleton except for the dorsal surface of the abdomen which is covered by the hind wings and the elytra.

ORDER: 22 Strepsiptera e.g. Stylopids. 1. these are small economically unimportant insects. 2. the larvare are endiparasitic in other insects and they are used in biological control. 3. antennae are thick and prominent. 4. poorly developed mouth parts of biting type. 5. larval development is hyper metamorphic. 6. the fore wings are small and club like, but the hind wings are large and fan like. 7. the most commin host of stylopids are bees and other social hymenoptera. 8. compound eyes are well developed but very much reduced.

ORDER23: Mecoptera e.g. Scorpion flies. 1. small, moderate size with 2 pairs of large similar membranous veins showing a pattern of dark markings. 2. Antennae are long and filamentous. 3. biting mouth parts at the end of a snout. Short cerci are present. 4. development is holometablic with caterpillar like larvae. 5. the legs are well developed with claws. The insects are called scorpion flies because in males, the terminal abdominal segment looks like the scorpion. 6. they are terrestrial and carnivorous in habit.

ORDER: 24 Trichoptera e.g. caddis flies. 1. the caddis flies are known as the case worms as the larvae may case us in the streams and lakes. 2. the adult are moth like with the presence of hairs on the wings instead of scales and nocturnal in habit. 3. the eggs are laid in stones and other submerged objects. 4. the larvae makes a case with sands, small shells, bits of leaves etc and lives inside. 5. they can spin a cocoon by the secretion of the silk glands. 6. the caddis flies are economically important and the young usually respire with the help of the external abdominal gills. 7. mouth parts are with mandibles and greatly reduced.

ORDER: 25 Lepidoptera e.g. butterflies and moths. though butterflies and moths have similar morphological characteristics, they differ in the following aspects: ] 1. butterflies are attractive and brightly colored where as moths are dull colored / pale brownish in colors. 2. the butterflies are diurnal whereas moths are nocturnal in habit 3. butterflies flap their wings vertical at rest and in moths the wings are spread out parallel to the substratum.

General characteristics: 1. small to large insects with 2 pairs of large membranous wings covered with minute flattened scales. 2. body and legs also in scales and hairs. 3. mouth parts consist of a long tubular proboscis formed from the maxillae which are of sucking type. 4. antennae clubbed, tapering or feathery. 5. development is complete. 6. larvae of soft bodied caterpillar with a hard head capsule and well developed biting mouth parts. 7. three pairs of 2 jointed legs. 8. pupae with limbs, with smoothly enclosed usually in a silk and cocoon or earthen cell. ORDER: 26 Diptera e.g. flies and mosquitoes. 1. the members of this order are mostly highly evolved order of insects which are transmitters of diseases or act as vectors. 2. the adult do posses only a pair of wings, biology of diptera are extremely diverse particularly regarding the habitat and the feeding behavior of the larvae. 3. some are scavengers, others attack living plants while others again are parasitic. 4. most of them transmit serious diseases in man like malaria, yellow fever, sleeping sickness and elephantiasis. 5. compound eyes are large and 3 ocilli are present. Mouth parts are piercing and sucking type or sponging type feeding on blood of vertebrates, plant sap and some are predacious. 6. the hind wings are modified into specialized balancing organs called halteres. 7. larvae are legless and last larval skin is retained as an outer covering to the pupae forming a puparium.

ORDER: 27 Siphonaptera. E.g. fleas 1. fleas are small apterous with laterally compressed body. 2. adults are ectoparasites and blood sucking and feeding on warm blooded animals while larvae are free living. 3. compound eyes are absent. Antennae are short and thickened. 4. mouth parts are modified for piercing and sucking type 5. legs are adapted for jumping. 6. development is holometabolous with legless maggot like larvae.

ORDER 28: Hymenoptera e.g. ants’ wasps, bees etc. 1. Minute to moderate sized insects with 2 pairs of membranous wings – the hind wings are always smaller than the forewings. 2. mouth parts are biting and chewing type with well developed mandibles and in honey bees they are modified for molding wax. 3. development is holometabolous, larvae soft bodied legless except the larva of the saw files and are called as maggots. 4. Compound eyes are well developed and usually with 3 ocilli. 5. the characteristic feature is that these insects are parasitized by insects of other orders and are termed as parasitism.

METAMORPHOSIS IN INSECTS Insects usually hatch in a condition morphologically different from that of the adult. Consequently they have to pass through changes in from which are collectively termed as metamorphosis. The term ‘metamorphosis’ is derived from the two greek words meta= change, morphe = form, designating a change in the form. Insects metamorphosis has been defined as the transformation of an immature larval individual into a sexually matured adult of different form, structure and habit of life. Variations in insect life cycle are almost infinite. The most conspicuous difference in the life cycle of insects are co related the kind of metamorphosis involved i.e. the manner in which they develop from an egg into an adult. Kinds: there are various degrees of metamorphosis found in insects depending on the conspicuous external changes during development. Classification of insects often depends on the type of metamorphosis. 1. Ametabola / Ametamorphosis. 2. Metabola • Pauro metabola (gradual metamorphosis) • Hemi metabola (incomplete metamorphosis) • Holo metabola( complete metamorphosis) • Hyper metabola. 1.) Ametabola / Ametamorphosis: Some species of insects show no metamorphosis, the eggs hatch soon after heing laid or even while in the body of the mother. The young insects coming out are like the adult except in size, colour, armature etc. as they grow, they move several times finally reaching sexual maturity and the adult functions. This group includes the order collembolan( spring tails), thysanura(silver fish) and protura(proturans) and it belongs to the subclass apterygota containing primitive wingless insects.

2.) METABOLA: in the more advanced insects subclass (pterygota) distinct changes in form and size during growth and development are observed. It is divided into following subtypes. • Paurometabola (gradual metamorphosis): certain species undergo gradual external stages during development. The newly hatched or the immature young is called the nymph. It is active and sticky like the adults except in size and color and absence of wings and genital organs. It undergoes various modes to reach the adult stages then these stages of development are present, series of nymphs and then the adult. The growth of the body wings occur gradually between successive moulds. Paurometabolic are orthoptera(grasshopper, cockroaches), isopteran(white ants). Dermaptera( earwigs), hemiptera (aphids). They belong to the division exopterygota of the section.

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Hemimetabola(incomplete metamorphosis): in incomplete metamorphosis, the immature forms are aquatic and called as naiads. They breed by gills and have other aquatic habits, where the adults are terrestrial or aerial and respire by trachea. The naiads are similar to the adults except for the size, body proportion and lack of wings. However, they do not resemble the adult on much on the nymphs of parametabolous insects. The changes in the body from one instar to the next are more pronounced then in gradual metamorphosis but no conspicuous one in the case of complete metamorphosis. Stages of development are the egg, series of naiads and adult, when ready to leave the water, the naiads crawl upon some plant or other object, the body becomes dry, the exoskeleton splits along the back and the imago emerges to assume the aerial habits with tracheal respiration. Hemi metabolous orders are represented by odonata (dragon flies) ephemeroptera (mayflies) and plecoptera(stone flies)

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Holometabola(complete metamorphosis): life cycle of insect has complete or indirect metamorphosis comprising stages egg, larva(caterpillar, grub), pupa(chrysalis) or cocoon and the adult(imago). The newly hatched larva shows striking differences from the adult. It is usually worm like with short legs without wings and compound eyes with chewing mouth parts and its diet caries radically from that of the adult. It moults several times including a series of instars to become fully grown pupa in its resting stage between larva and adult, during which the larvae surrounds itself in a secreted case called the puparium and transforms itself into the imago or the adult. This is more specialized state of affairs than in the previous group. It permits the specialization of the young to a variety of habitats and niches quiet independently off the adult mode of life. Majority of the insect order belong to this group and are represented by Diptera(house fly, mosquito), Lepidoptera (butter flies and moths), Coleoptera(beetles), Hymenoptera(ants, bess, wasps) and they belong to the division endopteryogota of the subclass pterygota.

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Hypermetabola: its still more complex metamorphosis including the stages egg, larvae, pupa and the adult. The larva undergoes many instars and each instar differs in habit and food from the others e.g. brittle beetle.

HORMONAL CONTROL OF METAMORPHOSIS: CHANGES DURING METAMORPHOSIS ACCOMPANIED WITH GROWTH AND ECDYSIS. Hormones play an important role in Ecdysis and metamorphosis. The various factors controlling ecdysis and metamorphosis are as follows: • Brain hormone (BH): this is secreted by the neurosecretory cells of the brain. Chemically it is a lipid. It activates the corpora cardiaca, a component of the retro cerebral complex. • Prothoracic trophic hormone(PTTH): it is secreted by the corpora cardiaca and activated by the prothoracic gland. • Prothoracic gland hormone(PGH): Ecdysome, a hormone secreted in the prothoracic gland chiefly controls ecdysis.

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Juvenile hormone: the hormone is secreted by corporatta, a component of the upper cerebral complex which is a non steroic lipid. It prevents metamorphosis of the insect larva into the pupa under the influence of Ecdysone as long as the juvenile hormone remains active. Each moults simply results into a larger larvae. When juvenile hormone declines, the Ecdysone is free to bring about the chain born larvae in to the pupa and then to the adult.

LAC INSECT (Laccifer lacca) Productive insects: honey bees, silk moth, lac insects. Sub class: Pteryogta Division: Exopterygota. Order: Hemiptera Sub order: Homoptera. Family: Lacciferidae Sub family: Lacciferniae. Genus: Laccifer. Species: lacca True lac: 42,000 tons of lac produced. India and Thailand: 70% Bihar: 40% and other places are UP, MP, WB and orissa. Plants: Zizpypus mauritiana, Cajanus cajan, Acacia Arabica, Acacia catcher, Butea frondosa, Butea monosperma, Zizyphus jujuba. Moist and humid environment, rainfall-75 cm. • Type of strains: Lusmi strain, Schleicheria oleosa, Rangenui strain – red color. BIOLOGY AND BEHAVIOR OF INSECTS • Emerging nymphs are small, soft bodied, black eyes, 0,6 mm long, 3 pairs of legs, red in color. • Breathing pores, anus and mouth are present. • Lose eyes, antennae and legs are restored by the male whereas lost by the female. • Gill of the male is slipper shaped and horizontal • Gill of the female is spherical and vertical. • Pruning and cropping helps the lac insect to feed. • A sexually mature female has lac in her intestine. • Other insects cause about 70% damage to the lac insects. • Eublemma amabilus, Javensis, Holcocusa moritta, Tetrastichus purpurens • Ariculting- harvesting in the immature stage during april and may, kakti cropping – harvesting in the matured state during October and November. • Different froms of lac are: Erilac – immature lac; stick lac – from sticks; button lac – molten lac is poured to from button lac; dust lac – brush lac; shellac – seed and dust lac. PRODUCTVE INSECTS: The productive insects are those which produce certain substances essential for human beings. The products of insects have high commercial value. Some of the important productive insects are honey bees, lac insects, silk moths etc. Taxonomy: Lac insect. Sub class: pterygota Division: exopteryogota Order: Hemiptera Sub order: homoptera Family: Lacciferidae

Sub family: lacciferinae Genus: Laccifer Species: lacca. The lac insect Laccifer lacca secretes a laccinus hard substance called the lac. It is unique since it is the only one of animal origin. The lac insects secrete a hard encrustation over the body and the secretion takes the form of a brown resinous substance and it is the true lac cultivation. LAC CULTIVATION (countries) The important lac producing countries are India and Thailand. India produces about 70% of the total world production of lac which is about 42,000 tons. The important centres in India are bihar, which accounts for about 40% of the countries in total production. MP, WB, Orissa, Assam and UP. HOST PLANTS The most important host plants on which lac insects secrete encrustation are Zizyphus mauritiana, Zizypus jujube, Cajanus cajan, Accacia Arabica, Accacia catcher, Butea monosperma, Butea frondosa, Ficus religiosa. CLIMATIC CONDITIONS Lac cultivation can be carried out in forest and sub forest areas where suitable host trees grow. Places with annual rainfall of about 75 cm with moderate temperatures are quite suitable. Dry and arid places are unsuitable and very hot. Temperature and hot winds soften the lac injuring the female inside the cells. Therefore, the success of cultivation of lac insects depends on the climatic conditions also. STRAINS PRESENT There are two strains of lac insects that emerge. The strain that thrives on (Schleicheria oleosa – Kusmi) and the one that rouse upon other host plants are known as Rangeni strain because of the deeper color of the lac it produces. About 90% of the lac produced in India comes from rangeeni strain. BIOLOGY AND BEHAVIOR OF LAC INSECT The female insect lays eggs inside the encrustation. A single female can produce about 200 to 1000 nymphs on which about a third would be males. From an encrustation the nymphs may emerge from 2-3 weeks, but most of the nymphs come during the first 5 days. The nymphs are minute about 0.6 mm, long soft body pointed posterior deep red in color with black eyes and 3 pairs of legs. The wander about on the shoots and move mostly towards the tender branches and settle on them. They start feeding by piercing the shoot. The nymphs get settled there and don’t move about a day or two after settling down , they secrete resin over their body. The resin glands are distributed all over the cuticle except near the mouth parts, the anus and the breathing pres. The resinous covering increases in size with the growth of the insect. They moult thrice and become the adult. After the first moult, both the male and the female nymphs loose their eyes antennae and legs, but the males regain the lost appendages at the last moult and the female gain them. The female nymphs become swollen and there is no trace of segmentation. Finally at the posterior end of the abdomen of the female is bent and round in shape occupying the entire space of the cell. The males are winged or apterous and emerge out of the cell and only live for few days. The male has only a life span of 62 – 92 hours after emergence. The male and the female cell can be distinguished, the make cell grows up in its longitudinal axis and slipper like in appearance, the female cell has grown up in its vertical axis and spherical in shape. The larva then passes through the pupa and the pupal stages. The male copulates with the female and grows up very fast and then secretes the lac abundantly and the size of the insect and the case reaches several times than that of the male cells. The female insect is the chief producers of lac. At the time of oviposition, the anal tubercle is withdrawn and the eggs are laid inside the cell. The eggs are laid and the female shrinks in size, leaving some space at the posterior half of the cell. Oviposition period of incubation and emergence if nymphs are all greatly influenced by temperature.

ENEMIES Damage to the lac crops may be due to both insects and also by monkeys, squirrels, rats, birds and lizards. The insect damage accounts for about 60 to 70% loss. The insects that are enemies of the lac insects are both predatory and parasitic in nature. The former are more destructive than the latter. Euplemus tachardiae, Moritella javeus, Petrastichul purpurus, Eupelmus tachardiae are some of the parasites. They not only affect the quality of the lac produced, but also its quantity by the presence of their larvae, pupa. PRUNING AND CROPPING The lac hosts should have plenty of new growth with tender branches for feeding of the lac insects. To promote sufficient tender growth, the trees can be pruned. In an area all the host trees should not be continuously cultivated with lac. As it has deletrious effect on the vigor of the trees, cultivation by rotation is necessary. Blood lac is shown to be cut when the lac cells are red in color in the anterior half and orange in color in the anal region. The best blood lac should have thick and continuous encrustations and the branches are cut into sticks of 15 – 30 cm and tied to the host branches longitudinally by means of banana or jute fiber. INOCULATION Has to be done on a non rainy day. If brood from a particular host is free and is used year after year in the same locality, and on the same host it is likely deteriorative in quality. HARVESTING The cultivators cut the crop in an immature stage. Ari cutting in april and may and also as mature (kakti crop) and in octoberand November. Aricutting is harmful to the host plants hence it is discouraged. The lac encrustation are dislodged from the branches by scrapping with the knife. The scrapping should be done immediately after the harvest. This is to avoid damage by the predators. There are 5 types of lac 1. Erilac: the immature stage of the lac which is harvested before reaching maturity. 2. Stick lac: matured lac in the form of sticks are obtained on maturity of the crop. 3. Seed lac: the lac in the stick is obtained by scrapping and after washing. 4. dust lac: it is obtained by grinding the crystals of the lac. 5. Shell lac: it is obtained by heating both the seed and dust lac together. 6. Button lac: the molten lac is poured into dyes in a zinc sheet. Button’s lac is 7 cm long and 0.6 cm thick. Uses of Shell lac: 1. seed lac and shell lac are used mainly to manufacture French polish, floor polish, paintings, inks, electric insulators, ceiling wax etc. 2. for the manufacturing of varnishes, the shell lac is a raw material. 3. shell lac is used for painting the bottom and sides of boats and ships to prevent leakage. 4. shell lac is often used for filling hollows in ornaments. 5. in ayurveda, lac is mixed with other herbs for preparing ointments 6. it is also used as one of the ingredients for preparing oil, medicine to cure fever and rheumatism. 7. lac is also used for dying silk sarees. Preparation of the market lac is marketed as shell lac. It is manufactured manually and involves 3 stages that is the production of crushed lac, seed lac and shell lac. The lac encrustations are dislodged from the branches either by twisting them with hand, scrappin with a knife or by folding the branches through rollers as in a cotton gin. The space between 2 rollers is adjusted that only the encrustation gets dislodged. The scrapping should be done as immediately as possible after to avoid damage by predators. The scrapped material is known as raw lac, scrapped or stick lac and it should be left in the sun for long.

It is necessary that fumigation with sulfur must be done for storage the stick lac is disintegrated and the powdery material is called as the crushed lac. It is then immersed in water in a stone or cement tubs for 3 days and often stirred well. The supernatant, crimson colored liquid is drained off, the material is then transferred to large oven to which lime is added. Now, the lac dye settles down and is collected, the suspended lac is filtered though the cloth. The process is repeated thrice or four times. The material is spread in the cement floor and allowed to dry. It is called as the seed lac or grain lac. From seed lac, shell lac is manufactured by large scale solvent extraction process by hot melting method. Coloring is given by addition of arsenic sulfide. Preparation of Shell lac: Shell lac is the purest form of lac. Crude lac which is obtained by scrapping the encrustation over the twigs is called as stick lac. Stick lac is not used for any purpose without being processed; the process of refining stick lac can be divided into 2 phases: 1st phase: it consists of stick lac being treated to the following process of crushing, sieving, washing, drying, clearing by winnowing in order to obtain the seed lac. • Crushing: to expose the inner surface of the lac shell, the stick lac is crushed by hand or by power driven grooved roll mills. • Sieving: te crushed lac is sieved though the proper mesh before washing and bigger sizes are recrushed for some factories. Sieving is done by mechanical sieves. • Washing: in some factories, washing of the lac is done by putting the crushed lac into the cupshaped stone wells mixing with water and rubbing the wet lac by feet against the sites of wax in order to remove the dye from the resin particle. The colored water is drained out and wasted lac is known as sed lac which is then dried in shade. The lac dye was formerly used which was retained from the colored water by precipitating with lime, but it has now lost its market. The colored water is at present allowed to flow out into the neighboring fields. in the bigger factories the washing is done by churning the crushed lac in a horizontal steel barrel fitted with agitators and through which a continuous flow of water is maintained after washing the lac to the desired extent. The washed material is then transferred to the stone wax, where the lac grains are separated from the sand and the product is given a final wash. The sand can also be separated by the use of sand separating machine developed at the Indian lac research institute and then subjected to drying. • Winnowing: dry seed lac still contains very small particles of sand, some woody matter and oter impurities and these are removed by winnowing and in this operation seed lac is also graded into dofferent fractions according to the particle size. 2nd phase: the impurities which are loosely present in the lac in the first phase were removed along with water soluble material. The impurities which are still sticking to the lac grains are to be removed in the phase of refining. This is done by hot filtration of moulting the lac or by sissolving the seed lac in a suitable solvent. • Indigenous method: the present method of indigenous manufacture is based on the principle of hot filtration. For this purpose, seed lac is poured in long cloth bags of about 62.5 mm in diameter. One end of the bad is tied to the axel of the wheel which is rotated during the operation by labor and is held lightly by a welter on a plat from nearer to the other side of the specially designed charcoal oven. The lac resin is fused or melted by the heat and squeezed by the twisting of the bag oozed out through the pores of the cloth. The melter scrapes out the molten mass and places it on a porcelain cylinder filled with hot water. Another labor then spreads the molten mass with a palm leaf on the other surface of the cylinder, polishes with a piece of cloth and then removes the stretched sheets. From the surface of the porcelain cylinder, we can pbtain sheets of shellac after cooling and is broken up into small pieces which is the hand made shell lac. Sometimes, the molten masses are poured on a metal sheet to form small circular disc and is called the button lac. The other methods followed in the 2nd phase are hydraulic press method and solvent method.

SILK WORM Class: insecta Subclass: pteryogta Division: Endopterygota Order: Lepidoptera Sub order: Frenate Family: Satumioidea Sub family: Bombycidae Saturnidae. Family Saturnidae

Sub family I Bombycidae e.g. Bombyxmori mesidonalis (Mulberry silkworm)

Sub family II Saturnidae Antheraca phihia(Indian tassar silk worm) Anteraea fritti(wild mugaworm) Antheraea aasama (Indian muga worm) Thiophilia religiosal (Dev muga worm) Attacus cynthea (wilderi worm) Philosomia ricini (Eri silk worm)

INTRODUCTION Silk is a valuable natural protein produced by certain insects. Various insects like Lepidoptera in their larval stages, wasp in adult, from the salivary gland, Embioptera from their tarsal gland and coleopteran and Neuroptera from malphigian tubules produce silk. Of them, the caterpillar of silk moth secretes the silk threads which are of the commercially important raw silk. HISTORY the Chinese first knew the art of producing silk from the cocoons of the silk moths as early as 2600 B.C. by knowing the immense value and the beauty of the silk rearing from silk worm spread over the world. The main centres in India producing silk are Karnataka, Bengal, assam, Punjab, Tamil Nadu and Kashmir. TYPES AND BIOLOGY OF SILK MOTH India produces all the four commercial varieties of natural silk namely mulberry tassar, eri and muga. 1. Mulberry silk worm (Bombyxmori meridionalis): it belongsto the family Bombicidae. It is totally domesticated insect and never found in wild state. The silk worm is extensively reared in many countries. The adult moth is sluggish and measuring about 2.5 cm long. After emerging from the cocoon, the adult lives for about 3 days only. After mating, the female lays 300 to 400 eggs which are seed like and brownish white in color. The eggs are laid in masses; the eggs are hatched in 8-16 days. The hatched cateroillar are 3 mm long and are dark in color. The larval stage lasts for about 28 to 30 days. During the larval stage, the caterpillar moults about 4 times. The fully grown caterpillar, is yellowish white in color growing to the length of 5 cm. the cylindrical caterpillar has a small anal horn in the last segment. It has 3 pairs of true legs and 5

pairs of false legs in the abdomen. It produces a long continuous strand of silk to form an oval cocoon and takes 12 days for constructing. Pupation takes place inside the cocoon and adult emerges in 10-12 days, life cycle is completed in 6-8 weeks. 2. Tassar silk worm: it is usually found in forest areas, feeding on their host plants like Zizypus mauritiana, Shorea robusta, Ficus religiosa. Eggs are laid on tender leaves of host trees and a moth lays about 200 eggs. Egg stage lasts for 8 – 10 days. The caterpillars are short and the larval period is 35 – 70 days. The pupal period is 25 – 50 days. The moth is stout with yellowish or brown wings with an eyespot on each wing. The moths do not mate in captivity and so the caterpillar cannot be domesticated. The cocoons are collected from the host trees in the jungle. The pupae have to be killed before emergent of the moths to prevent cutting of the silk thread into pieces. 3. Eri silk worm: this belongs to family Saturnidae. The adult moth is darkish brown and white in color. It lays about 120 – 200 eggs in clusters which hatch in 7 – 10 days. The larval stage lasts fr 17 – 25 days. The caterpillars feed on castor leaves. It can pupate anywhere and so no chandraki is necessary the cocoon is not compact but loosely spun. Silk is white or brick red in color and not as glossy as the mulberry silk. 4. Muga silk worm: resemblance between tassar and is found in assam. SILK GLANDS: The silk worm has a pair of salivary glands. It is situated in the latero ventral side of the alimentary canal. It is about 20 – 25 cm in each gland and anterior is a narrow duct. The middle enlarged part and the posterior narrow part are present. The 2 anterior ducts unite with each other to form a short common duct. The common duct opens out at the apex of the median cylindrical structure. The spinnart opens out on the anterior margin of the labium. The sides in the common duct paired “fillipits of the lyonnets” gland. An accessory structure is also found. The caterpillar are actively feedinf on the mulberry leaves. They have cutting and chewing type of mouth parts. In which the mandibles are well developed. At the time of cocoon formation, the caterpillar becomes sluggish and stops feeding. The salivary glands secrete a vicious secretion which becomes a fine filament on contact with the air. The filament contains 75% of tough elastic protein. The fibroin and 25% of a gelatinous protein Sericin. The former is made up of amino acids like Glycine, Alanine, Tyrosine and the latter of serine, the outer gummy layer of the silk thread. The silk thread is elastic, resistant and a non conductor of heat and electricity. It has a good tensile strength nearly as great as steel and is used in textile industry for surgical sutures, parachutes etc A single caterpillar is capable of producing 650 – 1300 meters of silk thread. MORICULTURE: the mulberry silk worm feeds on the larvae of the mulberry plants. The cultivation ok mulberry plats for rearing the silk worm is known as moriculture. The fertilized eggs are available from the grainage (where eggs are produced). The eggs must be disease free. The eggs are incubated under the optimum temperature of 25 – 30 C. the humidity must be between 70 and 80%. The hatched out larvae are transferred to bamboo trays, in which the paddy husk is spread and the chopped mulberry leaves are kept. The leaves are changed for every 3 hours for the first 3 days. From the 4th day, the caterpillar can be fed with full leaves. The caterpillars are voracious feeders and the consumption of leaves increase corresponding with age. The unused leaves and the excreta must be removed periodically. This process is known as cleaning. The fully grown caterpillars are uniformly spread on the chandraki for pupation. The cocoons formed are found attached on chandraki. The pupae must be killd 2 or 3 days before the complete emergence of the moths. Otherwise, the silk thread is cut into pieces. The cocoons are exposed in sunlight or hot air is blown over them or by fumigating with toxic chemicals. This process is known as stilling. The stilled cocoons are soaked with water to soften the gum that binds the silk threads. The threads from 400 – 500 cocoons are put in a spoon on wheeling machine and this a single thread is

made. This raw silk which forms about 60% and the remaining 40% is the coarse silk. The raw silk is further processed and marketed. REARING OF SILK WORM: The practice of silkworms for obtaining silk is called as sericulture. The accessories required for successful rearing of silkworms are: 1. A bamboo racked to keep the trays containing the various stages of the insect. The rack should have ant pacers at the base of the stand. 2. many circular trays made of split bamboo for draining. 3. many bamboos. 4. chopping knife for cutting leaves and chandraki or cocoonage which is a circular basket with a spiral wall about 5 cm width to facilitate the worms to attack their cocoons to them. The silk worm can be reared in places where the temperature ranges from 25 to 30 C and humidity from 70 to 80%. USES OF SILK WORMS The silk worms are useful in a few other ways. The chrysalids obtained from cocoons are dried and since they are rich in proteins are used as fertilizers. The fatty mater is used for soap manufacture. By cutting the lower lip of the dead larvae and pressing out the salivary fluid, long silken thread can be obtained. DISEASES OF SILK WORM They are susceptible to bacterial, fungal and protozoan diseases. The common diseases of silk worms are described below: 1. Muscardine: this is a fungal disease caused by Beauvaria bassania. The disease is spread through wind. The spores are carried by the wind and they lay on the skin of the caterpillar and they germinate. The germinating tube penetrates through the skin in the body and later grows into a mycelium. The mycelium comes in contact with the body fluid and forms a cylindrical spore. The secondary spore is also formed by budding. The secondary spore germinates within the body fluid and the mycelia penetrate the various organs of the body cavity. The symptoms of this disease are: • The infected worm becomes inactive and loses its appetite. • The body of the worm becomes limb and its elasticity is also lost. • In the skin, the characteristic specs appear. • The body becomes rigid immediately after the death and the body surface is covered with white spores. 2. Flacherie: it is common disease of the silkworm. The bacteria Bacillus bombysepticus and Mirococcus are responsible for this disease. Some claim that the disease is caused due to physiological disorders. The following symptoms can be observed in the infected worms: • The diseased silkworms lose their appetite and become sluggish in their movement. • The skin loses its natural glossy appearances. • The skin faeces become soft and stick to one another. The faeces later on becomes liquid and with foul odor. • The moulted skin, may not be shed properly, • The body color of the affected worm changes to balck in color. • Finally, the worms become motionless and putrefaction sets in. 3. Pebrine: this disease is caused by the protozoan parasite Mosema bombycis. It is the common disease and found throughout the world. This disease is spread from the infected moth to the caterpillar though the eggs. Generally, the parasite attacks the last instar of the caterpillars. The common symptoms of the disease are the following: • The larvae stops feeding.

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Ecdysis or moulting does not take place. Dark brown or black spots appear all over the body. The caterpillar finally becomes inactive and dies.

4. Grasseire: the last instar of the caterpillar is affected. They become swollen and test like a bag of granules. The body fluid becomes thickened and cloudy and they die. The curvature agent is nuclear. A kind of virus is responsible for this disease. The symptoms of this disease are: • The formation of polyhydral bodies on the skin. • The tissues are diseased. 5. Court’s disease: (Jachcinid parasite). Sometimes, pupa is formed without cocoon. The cocoon formed is very small in size. This disease may be due to malnutrition of food. 6. Grating disease: the anterior region of the caterpillar becomes translucent due to the infection of the bacteria Streptococcus bombycis. The ultra violet rays are also responsible for this disease. CONTROL MEASURES: 1. everyday, the skin of the caterpillar should be carefully observed whether any worm is infested with the disease. 2. if any worm is infested, it should be immediately removed from the batches. 3. eggs should be selected from the healthy moths. The Pebrine disease can be thus prevented. 4. proper spacing and the periodical changing of silkworm beds with paddy husks will also prevent the spreading of the disease. 5. proper ventilation in hygienic conditions are necessary for rearing healthy silkworms.

HONEY BEES Apis dorsata (the rock bee). It is the largest of the honey bees. It builds a single open comb in the branches of the tree. Along the sides of the step rocks in the forest and even in the walls of ratters and other parts of buildings. They produce plenty of honey and the annual honey from a colony is 37 kg. it is impossible to domesticate it because of its irritable and ferocious nature, peculiar hives and its habit of deserting the hives often but professional honey gatherers collect honey and wax from wild colonies often killing the entire colony in the process. Cutting and sponging type of mouth parts: here the mandibles are produced into the sharp balde and the maxillae push it in to long probing styles. E.g. Diptera. Sponging type: this type of mouth parst is similar to cutting and sponging type but in this case the mandible and maxillae are non functional, the remaining parts from a probus with the sponge like apex or lamella. E.g. non biting flies including the housefly. Certain solid food like sugar are eaten by the fly with this type of mouth parts. The insect extrudes a droplet of saliva on the food which dissolves in the saliva, the solution is then drawn up by the mouth as a liquid. Chewing and lapping type of mouth parts: here the mandible and the labellum are of chewing type and are used for grasping prey or moulding wax as nest material. The maxillae and labium are developed into flattened, elongated structures called as the glossa. The maxillae and labium fit up against the glossa from which the saliva is discharged and food is drawn. E.g. bees and wasps. Piercing and sucking type: the mouth parts of many groups are modified to pierce and suck the juice. In this case, the labium, mandible and maxillae are slender, long and fit to form a hollow needle. To feed, the insect inserts the needle into the host tissue and sucks the host tissue through the needle. E.g. aphids, leaf hoppers, scale insects, strideri, mosquitoes, bed bugs, lice and fleas. Siphoning and tube type: here the liquid food is sucked up by means of long proboscis composed of only of the united gallia of each maxillan and forms the tubes which opens into the oesophagus e.g. Lepidoptera feed on liquid food. Grub: larvae of an insect especially beetles, maggots or small caterpillar. Ear head: the seed bearing head of spice of a cereal plant. Gluree: membranous back surrounding the spikelet of grass/ floret of sedges. Panicle: the lose branching of cluster of flowers. Apis indica: it is the common Indian bee found both in the forest as well as in plains through ought our country. It is smaller than rock bee but longer than little bee. It builds combs in the cavities and hollows of trees, caves and hidden sides. The annual yield of honey is 2 – 5 kg / colony. Apis florae: it is known as the little bee, since it is the smallest of the 3 species of Apis. It is seen only in plans. It also builds single, but small combs on bushy plants and corners of roofs. It yields very little honey about 0.5 – 1 kg per year from a colony and so it is not domesticated and reared. Apis mellifera: the malicious bees reared in Europe and USA. It shows a very high annual yield of 50 – 180 kgs per year. In India, the species are reared in aperies of Kashmir and Punjab. Meliponna irridipennis: the dammer bee is tiny with a vestigial sting. It inhabits the cervices in walls an hallow trunks of trees. The comb is made up of dark material called cerumbin it is a mixture of wax, earth ir resin, it is a very poor honey gatherer and yields only 60 – 180 ml /colony/ year.

MORPHOLOGY OF HONEY BEES: The body of the honey bee is divided into the head, thorax and the abdomen. Head: the head of the honey bee is triangular with 2 large compound eyes and 3 ocilli. The number of ommatidia in an eye are about 4000 in queen, 5000 in worker and 8000 in drone. Bees recognize objects with their compound eyes, precise movement and distinguish color and forms. They can distinguish only yellow, blue, and green and cannot see black red or grey colors. The mouth parts are of chewing and lapping type. The mandible and labrum are well developed for chewing type. The labium and maxilla re integrated to form a lapping tongue, proboscis, the labial glossa is modified into long, elongate, hairy, extensible sucking organ which can be protracted or retracted to reach deep into the nectarines of tubular flowers. The glossa is followed by labellum / bauton at its apex. The length of the proboscis is 6mm in worker, 3- 5 mm in queen and 4 mm in drone, the accessory like labial palp, maxillary palp, the prementum, sub mentum, galea, are all well developed; also the stipes. The mandibles in honey bees are not mainly concerned with feeding, but are put into various other uses. In the worderbee, apart from serving as grasping organs, they help in the injection of pollen grains, in manipulation of wax in the comb, mainly in building, in supporting the proboscis when the latter is not in use.

The thorax: thorax consists of prothorax, mesothorax and metathorax. From meso and meta thorax, haired wings are developed. Each thoracic segment consists of 2 legs. The legs of the honey bee consists of 6 segments, the coax, femur, trochanter, tibia, tarsus and pre tarsus. In the first pair of legs, there is an antenna cleaner. To this, the antenna is drawn and cleaned. The third pair of legs are modified for collecting pollen from the flower. Each of the 3rd pair has the pollen basket, the pollen pocket and the pollen comb. Abdomen: it has 9 segments. The first abdominal segment is fused with the metathorax to from propodium. In the segment, 4 – 7 pairs of wax glands are present. In wax glands, secreted the fluid secretion which hardens and deposition on the surface of the wax plates. The workers collect the wax from the wax plates and construct the combs. In the last segment of the abdomen of the workers and queen, a pointed sting is present. A poison gland lies in the 7th segment. It is a modified gland of the reproductive organ. The poison gland is an organ of defense, royal jelly INTERNAL ANATOMY Alimentary canal: mouth cavity deeps into the pharynx and then into the esophagus, which is a long narrow tube, which leads to the dilated sac like crop called the honey stomach. It serves as a reservoir for the liquid required. The crop is followed by a neck like proventriculus which is long and broad. At

its junction with the crop, it has a x like aperture provided with 4 triangular lips. The opening of the proventriculus into the true stomach or ventriculus, is guarded by a well developed valve. The function of the proventriculus is to pump the food from the crop into the ventriculus and to prevent regurgitating from the latter. Pro ventriculus is ‘U’ shaped and forms the larges part of the alimentary canal. At the junction of the ventricules with the ileum, there are about 100 malphigian tubules. The ileum is a looped simple tube. The rectum is large, broad and its anterior end has six papillae. Salivary glands: there are 2 pairs situated in the head and the thorax region. They are vestigial or absent in the drones, but developed in the queens and workers. The thoracic glands are present in all the three castes of the honey bees. The secretion of the salivary gland has the enzyme invertase which reduces the sucrose of the nectar in to levulose and dextrose of honey in the crop. The crop has no gland. In the head, there is a pair of lateral pharyngeal gland whose secretion makes up the royal jelly used for feeding the young ones of the bees. Circulatory system: consists of the heart located in the dorsal apex of the abdomen and all aorta extending through the thorax into the head where it opens beneath the brain. Respiratory system: the tracheal system has two pairs of spiracles opening in the meso and meta thorax, propodium and the next of abdominal segments the trachea in honey bees are characterized by the development into the elaborate air sac. Nervous system: the brain consists of proto cerebral and deuterocerebral. The brain is also followed by some esophagal ganglion and the ventral nerve code consists of ganglia. The size of the brain differs considerably in the 3 pairs of honey bees. The head of the drone is the largest. The brain of the drone appears to the largest, but is due to the greater development of the optic lobes. Reproductive system: the male reproductive organ consists of a paired testes, vasa deferntia, casicular seminacles and paired accessory gland. The female reproductive organ includes a par of ovary, oviducts, alkaline glands. Each ovary is made up of numerous ovarian follicles. STRUCTURAL ADAPTATION IN HONEY BEES: Mandibular glands: there is a pair of mandibular gland one in each side associated with the mandible the function of the gland secretions is for softening the wax. The glands are vestigial in drones and larger in queens. Lateral pharyngeal gland: there is a pair of lateral pharyngeal gland situated in the anterior dorsal region of the head. The glands are well developed in workers, vestigial in queens and absent in drones. They produce nutritive food called the royal jelly or bee milk, which is used for feeding the queen, larvae, drones and the workers. Workers in the second week of their life produce royal jelly and these bees are called as feeders. The feeding bees obtain royal jelly by threshing the end of their proboscis over the base of the glossa of the feeder bee. However in feeding the larvae, the royal jelly, gets discharged between the mandibles into the brood cells of the combs containing the larvae. The glands are fully functional and active in young workers which serve as nurse bees. But the glands cells are seen emptied or atrophied in older bees which go on foraging. Legs: in the forelegs of all 3 castes of bees, the brushes of stiff hairs are present on the inner surfaces. These hairs are useful for drawing pollen and other particles from the head, eyes and the mouth parts. The most important feature of the foreleg is the antenna cleaner. There are 3 pairs of legs in honey bees (foreleg, middleleg and hindleg). Since the antenna have important sense organs, insects are careful to keep their antenna clean of all dirt. The antenna cleaner is situated in the inner margin of each foreleg. The different pair in legs are: 1.) tarsal brush 2.) antenna cleaner 3.) Basitarsus 4.) Clasp and tibia.

Pollen constitutes an important part of the food to both the larva and adult bees and it’s the principle source of protein to the bees. Propolis is a resinous substance available in the heads of the trees and issued by the bees for reparing the crack in the hives and also for strengthening the wax in comb building. Both pollen and proboscis are collected and carried to the hives by the bees in the back in hind tibia. In the worker bees, the hind legs are larger in size than in the other 2 castes. The smooth outer surface of tibia is fringed with long curved hairs forming the pollen brush or slopa and which is followed by pollen basket and corbicula. When the basitarsal brushes of the hind leg are loaded with the pollen. The leg of one side is scrapped on the other in such a manner that the bunch of hairs on the enf of the tibia scrap out a small mass of pollen from the tarsal brush of the opposite legs. By repeating the process, the little masses of pollen are pushed into the corbicula which ultimatelybecomes fully loaded with pollen. With fully loaded pollen basket, the foraging bee returns to the hive, goes into the comb, where the pollen is to be stored, sits over the cell resting the forelegs on the cell edge with the abdomen curved and the hind leg stretch into the cell. The basitarssy of middle leg move out over the pollen basket and dislodge the pollen into the cell. Wax glands: 4 pairs of wax glands are present in the ventral side of the abdominal segment 4 – 7. below these glands are the wax plates or wax mirror being present. The secretion of the gland is carried through the cuticle and the wax hardens on the outer surface of the wax proteins. The wax is removed by the basitarsi where it is taken off by the mandibles and masticated. The bee then deposits it on the comb under construction. Sting: this is the modified oviposition supplied with poison and serves as an instrument of defence. The poison gland consists of a pair of arid gland which meets inside the poison sac. The arid gland mainly consists of formic acid and it’s the venom of the bee’s sting. There is also another gland, the alkaline gland and its secretion is not known. The bee colony: in a bee colony of an average size, there are about 30,000 – 50,000 of bees. It consists of normally of a queen, and a few hundred drones and the remaining 90% of the population of the workers. Each time has certain specific function showing the phenomenon of division of labour.

hind leg of worker

leg of worker bee

Queen: the queen is the functional and a mature female of the colony and one is found in a normal colony. The queen is larger than the drone and workers but the head is smaller. She has no wax plates, wax glands and a pollen basket. A conspicuous oviposture functions as the sting. The queen is raised in the special cell constructed at the lower border of the comb and the cell is much larger than the other. The egg hatches in 3 days. The larva is fed with royal jelly, a nutritious good rich in protein 40 – 43% by workers. The larval stage lasts for 5 days. The pupal stage lasts for 7 days and finally the adult emerges out. An ectodermal exudates or hormone commonly called as queen sub is being secreted by the queen. When the pheromone is plenty, it is being licked by the workers and this inhibits the workers from proceeding to the queens and only workers are produced. This type of control of caste is known as ectodermal control. The queen is the mother of the colony and the centre of the activities and binding forces. The function of queen is to take part in nuptial flight and to reproduce and maintain the colony strong. The spermatozoa received during mating are sufficient to last for the entire life period of 2 – 3 years. Once she sits for egg laying, she does not take up anymore nuptial flight. She lays about 500 eggs in prosperous section and she lacks the motherly instinct of rearing the larva which is done by the nurse bees. When the queen becomes old and is unable to fertilize the egg, another queen is reared and the old one is discarded. Workers: the worker is the imperfectly developed female and the smallest member in the colony. The workers are selfless members of the colony and dedicate the time and attention to the service of the

colony ever since the time they emerged as adult. Young workers do all the domestic activities inside the colony like secretion (feeder bees) and feeding young ones with royal jelly (nurse bees) building and repairing combs with wax secreted by them, attending on the queen, keep the hives warm, clean, defending the colony from enemies. Many of the experienced old workers go out on foraging for the collection of pollen, nectar and propolis. The workers are raised in the cell situated in the lower part of the comb. The workers head are hexagonal in shape and covered with flat caps the queen lays fertilized eggs each in a cell and the eggs hatches in 3 days, the larval stage for 4 days and the larva is fed by the young nurse bees with royal jelly and the bee bread and partially digested pollen. The adult worker on emergence lives about 45 to 80 days and is confined with the hive for three weeks attending various duties. They are called as household bees or nurse bees. They attending in cleaning the hive and incubate first 3 days of their life cycle and feeding the larva for next 3 or 4 days. They secrete the royal jelly, wax for comb building during 2 weeks and receive honey from the foraging bees and store it in combs in the third week. Foraging of the bees: the field bees get activated in the morning by about 7 or 8 o clock depending upon the sunshine and temperature they go out on foraging and then collect pollen, nectar propolis and water and carry them to the hive by making a number of trips. The bees that go out first find out sources of these materials and are called as searcher bees and scout bees, they return to the hive and communicate the message to young foraging bees by means of definite patterns of dancing. They perform a round dance (in circles) clockwise and anti clock wise alternatively every one or 2 circles. If the source is nearby, a wag tail dance that is making a straight run and then a semicircle back to the beginning of the straight line, moving up the top of the run and a semi circle in the opposite direction and back to the beginning of the straight line indicating the direction of the food source. The honey bees usually forage within about 100 m distance from the hive and can go upto 1.5 km. they are capable of flying at a speed of 25 – 30 km/hr and the bees are most active in foraging within a temperature range of 25 – 27C. a bee carries upto 35% of the body weight of the pollen in one trip. The bee returns to the hive and pollen pellets are pushed down to appropriate cells by means of the middle leg. The workers make about 6000 trips to collect 500 – 1000 g of pollen. The nectar is being collected from the flowers and stored in the crop and contents are regurgitated and are stored in the combs and after natural ripening is capped. A worker makes about 1900 trips a day for collection of nectar. In addition to pollen and nectar, bees also collect propolis, a resinous substance exuded by buds, leaves of trees and shrubs and it is carried in the pollen basket by the workers and the house bees make use of this propolis by cementing into the cervices in the comb. Behavior of the honey bees: 1. Swarming: an important phenomenon in life history of bee colony is swarmind in certain seasons of the year usually November to march, it is the honey flow season and there is plenty of nectar available in plants and there is impulse of swarming. It is a potent instinct in bees for dispersal and precipitation of species. Various causes such as inconvenient location, congestion, want of breeding space, bad ventilation are the factors which accelerates the desire of swarming in bees. The strong colonies are the first to develop the instinct, the presence of a drone brood usually on the 2 sides of the comb is the first symptom for swarming. Also few queen cells are constructed along the lower border of the brood combs and fertilized egg is laid in. the inmates attain the pupal stage on a bright morning or number of bees will be seen hovering about all of a sudden in an excited mood near the hive. The queen comes out and is joined by half the workers and few drones which then settle in a tree or bush nearby and hang in cluster, the scout bees go in search of appropriate place for colonization and then the entire swarm now moves and settles in the site. The swarm which issues from the parent colony is the primary swarm. In the parent colony the new queen emerges in a about a week after the first swarm. If the population is again sufficiently strong in the present colony, the first emerging queen also moves out with the second swarm. Queens emerge subsequently and some proves is followed until parent colony is depleted to a minimum and the subsequent swarms are known as “after swarms” or “caste swarms”. If the

parent colony is weak after the issue of the primary swarm, the emerging queen destroys all the remaining queen brood cells. 2. Nuptial flight: the queen is the mother of the colony and the centre of all activities and binding force, the only function of the queen is to take part in the nuptial flight and reproduce. Mating takes place in the air during nuptial flight. A virgin queen is usually followed out of the hive by a swarm of drones. The queen may get mated twice, thrice or even five times during successive flights. The drone after mating falls dead and the queen returns to the hive with the part of the male organ detached from the drone and retained in her sting chamber. Fertilization takes place in the air and male gets killed because, he can eject the sperm only for generating great pressure in the abdomen with aid of muscles and fluid pressure of the blood. The spermatozoa received by the queen at one mating will be sufficient enough to last the entire life cycle of the queen. The queen lays about 500 eggs per day and deposits fertilized egg in small cells in the comb which develops into the workers and unfertilized eggs in large cells which develop into the drones. The insemination of the eggs take place in the vagina as the egg passes the opening of the spermatical duct. Due to the action of the muscle in the spermatical duct, the release of the spermatozoa can be regulated by the queen. BEE KEEPING: honey bees are reared in artificial hives for the honey, bee wax as they provide and for the help they render in pollinating crops. The practice of rearing bees is called as apiculture or bee keeping and the place where hives are maintained is called as an apiary. Different types of bee hives were in use in various parts of the country. They are pot hives, book hive, house hive, nucleus hive, daunt hive, British hive, Langstroth hive of all of these types, the one designed by Newton is the most popular one in south India. Renereut L.L. Langstroth in 1857 was the first to design a movable artifical bee hive. Newtons bee hive consists of the following parts: 1. Floor board: it is the board in which the entire hive rests. It is otherwise called as the alighting board and it has openings in the front with removable panels at the sides. The size of the floor board is 14” x 9 ½”. 2. brood chamber: both the bottom and the top of the sides of the brood chamber are the size in 9 ¾ “ x 8 ¼ x 6 ¾ with and entrance slit of 3 ½ x 3/8. there are 8 wooden frames which are fixed inside the chamber measuring about 25.4 x 14 cm and space provided between the frames are 0.6 cm. each wooden frame measures as 8 ¼ x 5 ¾ x 6. (Brood chamber: between the floor board and the super chamber). 3. Super chamber: it is placed between the brood chamber and top cover. The super chamber is open both in the top and the bottom and measures about ¾ x 8 ¼ x 3 ½. Eight separate wooden frames are being placed in the super chamber and measures about 8 ¼ x 5 ¾ x 2. 4. top cover: it has the same measurement as that of the brood and super chamber. The top cover is placed above the super chamber and consists of opening closed with wire gauze. 5. Roof: the roof is open at the bottom and is closed above by zinc sheets. 2 holes are situated for ventilation and holes are covered with wire gauze. The hives are usually painted yellow, light blue, green/pink. The hive has to be fixed over the termite proof stand a meter height, kept in shady place under the trees. It has to be protected from ants by providing oil bands on the stand or water troughs under them. Other accessories required are • comb foundation unit: it is made up of pure wax and its artificially provided for colonies. During honey flow season, by attracting them to the super frames by means of thread or fiber. • Dummy division board: it is an alternate to brood chamber and hence the bees can be confined to the limited space when population in hive is low. • Porter bee escape board or super cleaner: it is a board covering the brood chamber with one way opening in the centre. It is used to clean the super of the bees by keeping them in between super and brood chamber.

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Drone excluder or drone trap: drone trap is fixed in front of hive entrance. In the afternoon when the drones and workers come out for play flights the bigger groove at the back of the trap allows the drones to come up to front entrance. By finding difficult to escape through, they enter the combs which act as one way lanes. The workers can freely go out through the groove and the drones are this trapped and removed next morning and killed. Swarm trap: it is a rectangular box open at one of its border side and wire gauze fixed to about 2/3rd of its height on the other side. The 1/3rd portion on this side is fitted to a queen excluder sheet made up of zinc and placed in a slanting position. This box is placed close to the opening on the floor board and is tightly secured with a piece of string. One or two frames with comb foundation sheets are placed inside the box. When swarm issues, the queen along with few workers are trapped which can now be transferred to a hive at a desired place. Queen excluder: a queen excluder is placed over the loop of brood chamber sheet present that prevents the queen from having access to the upper chamber which results in the construction of queen cells in the upper hive. Smoker: it’s a small tin with an elastic bulb at one side and rag of cloth or any material to be burnt inside and the smoke is expelled at the desired spot. Honey extractor: it is equipment which consists of a cylindrical drum containing a rack or a box to hold super frames. The box is fixed to a rod at the centre and it is rotated with the help of 2 gear wheels. The frames with honey cells are decapped by a sharp knife, after dipping in hot water and fixed to the slots provided in the box which is rotated by the handle. The honey in the cells is forced out in the droplets by the action of centrifugal force and can be collected through the exit in the drum. As cells are constructed on both sides of the comb by changing the side of handles and again rotating, the honey can be drained out from other side.

LOCATION OF AN APIARY: An apiary should be located where there is abundance of nectar or pollen yielding plants. The site should not be exposed to strong winds. The site should be flat, but with good drainage facility. Clean and fresh running water should be available to the bees in or near the apiary. Should not be located near the highway. A good bartered wire fence or a hedge may be provided to keep out intruders. The site should be free from termites and black ants’ infestation. Bee pasturage: bees collect the nectar and pollen from plants. Nectar, a sweet solvent secretion from the floral and extract floral nectarines of flowers, is the raw material for honey. Pollen is a protein rich food. For the bees propolis which is obtained from the barks of the trees and buds are used for filling crevices in the honey comb. The plants that yield these materials are collectively known as pasturage. The period when a good number of plants have nectar is called honey flow period. The season when there is no honey flow is called dearth period. Plants yielding nectar to honey bees: the plants which are visited only for nectar by the honey bees are: tamarind (Tamarindus indicus), Neem (Azadirachtra indica), Suprent tree (Sapindus spp.), Eucalyptus spp, Pongum (Pongamia glabra), Horinda tindoria, Prosopis spicigera, Quisqualis indica, Segarea moths, Tribulus turestus, Gryqicidia maculate etc. of these, tamarind provides rich supply of nectar. Plants yielding nectar to honey bees: bananas, citrus, apple, peas, plum, peach, guava, mango, coconut, sesamum, safflower, mustard, cruciferous. Vegetables: bendi, onions, clover, casmos, hollyhock, aster species, acacia, cassafistula, polygonum spp, antigonon and cotton supply both nectar and pollen to the trees. Out of these cotton is a very rich source. The bee keeper has to cultivate a variety of crops in order to get plenty of honey in rotation.

honey extractor

Brood frame

Super frame

Swarm trap

Queen excluder sheet

INSECT PEST OF STORED PRODUCT It is well known that not only the crop plants in the field are attacked by insect pests but also different kinds of insects cause damage to several stored products. Prevention of the lost between the harvest and actual use will only increase the availability of stored food grains especially in countries like India where post harvest damage is considerably high. Loss is due to improper storage is estimated to be around 10% of the products. Hence the protection of stored products from loss due to insects and other pests and fungi etc. are as important as the control of pests and diseases in the field. Food grains are necessary to be stored after harvesting for shorter and longer intervals either for future consumption or for seed for the next cropping season. The improper storage will result in insect infestation and deterioration in quality and the loss incurred due to such attacks is always substantial. Hence the protection of such products stored in ware houses and godowns are of great importance since these provide undisturbed shelters, favorable environment and abundant food supply to the insects to reach the pest state is leveled in a short time. Generally the pest of crop plants in the field before harvesting has to face several adverse climatic conditions and will have to protect themselves against their predatory and parasitic enemies. The poor thermal conductivity of the stored products more or less provides a protected micro environment. The natural enemies i.e. the parasites and predators also find it difficult to reach the

insects which are inside the grain. There fore these pests are active through out the year unlike the seasonal activity of the preharvest pest. Based on the feeding habits and the behavior, stored products can be grouped into primary and secondary pests. The primary pests are more dangerous and loss incurred is very heavy because it results in the loss of quality of the produce while secondary pests are not likely to affect the quality to this extent, and in addition they can easily be removed before the material is marketed. On the basis of the method of feeding, the pests are grouped as internal or external feeders. The internal feeders are the primary pests because they feed on the kernels of the grain and since they lie inside the grain it is difficult to remove them. As a result, the quality and hence the market ability of the produce is lost. The external feeders are the secondary pests and they generally feed on the dust or on the broken surfaces of the kernels, because either by mechanical injury to the grain or by feeding of the primary grain pests hence it is possible to remove them by screening or fanning before marketing. Source of infestation: since these pests are capable of flying like bruched beetles in which infestation may start from the field itself. Such infestations are common in leguminous plants. Most of these pests continue their breeding even after storage. Generally most infestations occur only after the grains are stored. Such pests can be regarded as general feeders because they feed and breed on any dry food and storage places used by man. Such infestations occur from the storage bins or from ware houses that are not cleaned thoroughly before storage or infestation may occur due to migration of pests from near by sources of infested materials. CONTROL AND MANAGEMENT The pests of stored products can be controlled by preventive and curative techniques. The preventive methods are: 1. General cleanliness is a very important factor in the prevention of pests of stored products hence before storage the godowns are the storage bins and must be cleaned thoroughly and the broken infested materials are to be removed and destroyed. In addition all the crevices and holes in the store houses must be sealed. The bins used should be water proof. 2. when storing the grains, they should be thoroughly dried because extensive moisture produces heat, which favors the development of molds and this causes unpleasant odour and hence loss in quality. 3. proper ventilation must be provided when storing the bags in the godown and sufficient space must be allowed for periodical inspection and gunnage should be used for bag storage. 4. fresh materials should not be stocked along with old or infested stock. 5. as far as possible only one kind of produce should be stored in one place. 6. periodical inspection must be carried out to make sure if infestation has settled in. 7. after the rainy season, the stored products are to be sun dried to remove moisture. 8. to prevent infestation, spraying or fumigation with ethylene di bromide is recommended. Remedial or durative methods: On periodical examination, if an attack is noticed, the following steps can be taken to save the stored products. 1. the products can be once again sun dried and cleaned. 2. if the infestation is severe, fumigation (with hydrogen phosphide, phosphine, methyl bromide, ethylene dibromide, etc.) is recommended. This method is rapd and effective for destroying insects in the godowns. But many fumigants affect the viability of the seeds, particularly if the dosage used is excessive and seed moisture is high with high temperatures and excessive exposures. 3. the stored products like seeds can be mixed with carbaryl or malathion at 1:200 ratio by weight and this kind of treatment will be effective for one year.

EXTERNAL FEEDERS: Red flour beetle b.n : Triboleum castaneum family: Tenebeionidae order: coleoptera. 1. beetle generally attacks only damaged or broken grains and in severe infestation, the flour. 2. color of the flour product changes to grayish yellow, they become moldy and emit a pungent smell (unfit for human consumption). 3. beetle is small, flat and reddish brown in color. 4. head, thorax and abdomen are distinct with well developed antennae. 5. hibernate in winter, during spring they become active and start breeding. 6. each female lays 450 eggs, which are white, cylindrical, laid single in the flour or among grains. 7. they are sticky in nature and so are often covered by flour or dust and become difficult to identify. 8. depending on temperature, eggs hatch out in 4 – 12 days, the optimum temperature being 27C. 9. on hatching, the grub is small and covered with hairs. 10. larval period varied from 27 – 90 days depending on the temperature and food availability. 11. pupation occurs on the surface of the flour for 6 – 9 days. 12. life cycle lasts for nearly 6 weeks, but if the temperature is low, it lasts longer. 13. beetle is also known to infest grains, vegetable powders, seeds, dry fruits, oil cakes, nuts, etc. Indian meal moth b.n. Piodra interpauretella. Family: Phycitidae Order: Lepidoptera 1. moth has forewings with white bands. 2. it lays about 300 eggs in clusters and life cycle is completed in 5 – 6 weeks. 3. larvae feed on grains, ripe fruits etc. INSECT VECTORS OF PLANT VIRAL DISEASE Viruses attack both plants and animals are usually described as plant viruses and animal viruses. Specific diseases on specific parts of the plant species. All viruses are infectious and the transmission of some take place. 1. during propagation of plant grafting through seeds or through any propagating organ. 2. with the help of transmitting agents, all vectors like microbes, nematodes, any insects, fungi etc. get transmitted. Insects play an important role in transmission of viral diseases among plants and animals. Most of the insect vectors are from the order Homoptera which mainly includes sucking insects. Some diseases are also transmitted by chewing insects. Vectors of the yellow group of viruses are leaf hoppers, while mosaic group of viruses are transmitted in general by aphids. This shows that mechanically transmitted viruses are aphid from and the other viruses are leaf hopper from. There are differences among vectors in relationto the virus that they transmit. Some of the viruses remain viruliferous only for a short time of few minutes to a few hours in the vector and such viruses are called stylet – bone viruses while in others , the virus stays in the vector for a number of hours and finally the ingested virus is transmitted through the saliva of the vector. Such viruses are called propagative viruses.

Viruses are previously grouped into 2 categories as a.) non persistent viruses: A vector can transmit this virus soon after feeding on a diseased plant. The ability to transmit the virus is lost soon after the vector feeds on a healthy / immune plant. If the vector is b.) persistent viruses: the virus is consumed by vector along with its food and undergoes a period of maturation in the vectors body before it becomes infective. Insect vectors can now transmit the disease for lifetime. Importance of insects and their role in transmission of virus diseases in plants is to be emphasized in order to understand the vectors potential and disease caused, so as to develop control measures. Insect vector Virus Pentalonia migronerosa Banana bunchy top, Caudamon mosaic (marbled ‘katle’ disease) Aphis gossypii Papaya mosaic, cucumber mosaic, chilli mosaic. Myzus persicae Cucumber mosaic. Aphis craccivora Rhopalosiphum maidis Bemisia tabau Thrips tabaci

Cowpea mosaic, papaya mosaic. Sugarcane mosaic Bending, yellow vein, clearing, dolichos yellow mosaic, tobacco leaf curl, tomato leaf curl, papaya leaf curl. Tomato spotted wilt.

INTERNAL FEEDERS: Rice weevil: Sitophilus oryzae Family: Curculonidae Order: Coleoptera. This weevil has a world wide distribution and it is the one of the important pests of stored products especially paddy and rice. The adult is dark brown with a cylindrical body and conspicuously curved beak. The elyptera has four light reddish or yellowish spots. Both adults and larvae attack the grain on which they feed voraciously. As a result, the grain becomes useless for human consumption as well as for sieve purposes. If the infestation is heavy, the grain becomes the mass of broken vegetable matter. The attack of this pest is sudden and irregular and is more common in warm places with a humid climate. The adult female makes small holes in the soft part of the grains and the eggs are deposited inside the small hallowed out grooves and entry holes are covered with a gelatinous fluid. The eggs are whitish and oval in shape. A single female lays about 60 – 400 eggs in 4 – 5 months and they hatch in 4 days in summer and 4 – 6 days in winter. The apodous tiny grub is whitish in color with a yellowish brown head. They bore into the grain kernel and feed on the stacky content. Generally a grub is seen in each grain, but occasionally 2 – 3 grubs are also noticed. The pupation is inside the grain, the pupa is dirty white in color, but later changes into dark brown. The adult weevil lives for 4 – 5 months and starts breeding immediately after emergents, the life cycle ranges from 26 – 28 days and generally 4 – 5 generations are observed in a year. The adults hibernate during winter in the cracks and crevices of the godowns. This pest also attacks wheat, barley, maize, sorghum and other grains. Paddy borer beetle (The lesser grain borer). b.n: Rhyzopertha dominica Family: Bostrychidae Order: Coloeptera. The beetle occasionally becomes a serious sporadic local pest of stored paddy (unhusked rice). The adults bore through the husk of the grain, feed on the contents and turn into chaff. They destroy far

more than they can consume. The grubs also feed on the starchy content of the grain, leaving behind the husk only. The first stage larva, which is straight in outline, easily bores into the grain, but in the later stages of growth the larva becomes curved and so finds difficult to bore the grain. Such grubs feed on the waste flour left by the adults. The adult beetles are dark brown in color with some what rough surface. The head is bent under the thorax. Antennae are serrated and trisegmented. The audlts and grubs hibernate during winter. The female deposits the eggs on the grain near the embryo and through which the larva can easily bore the grain. A single female lays 300 – 500 eggs which are pear shaped and laid singly and hatch out in 5 – 11 days. The newly hatched larvae are active, feeding upon loose starchy material in the godown. The larva undergoes a period of 4 – 5 months after which it pupates. On an average, the larval period is 40 days. The fully grown larva is dirty white in color wth light brown head and curved abdomen and covered with tiny hairs. The prepupal and pupal periods lasts for 7 – 8 days and the total life cycle is about 2 months. Generally 5 generations take place in a year. This pest is also known to attack wheat. Angoumois (Grain and flour moth). b.n: Sitotroga cerealella Family: Gelechiidae Order: Lepidoptera. It is the most destructive pest of unmilled grain. Since it was first recorded (1796) as a pest in angoumois province of Fraince. It was laid as an angoumois moth. The initial infection occurs when the grain is in the milk stage in the field and usually a small percentage of grain kernels are thus infected. By the time the grain is thrashed and stored, the infection increases rapidly. The larvae cause the damage to the grain. In the early stages of infestations, the injury is more difficult to detect, because the larva bores its vein into the grain when very small. On gaining entry, it spins a silken web over the opening this making it difficult to locate the entry hole. On entering, the larva feeds on the kernel unseen and the first indication of the damage is provided, by the presence of moths in the stores of godown and the round holes in the grain. The infested grain is hallowed out due to the feeding of the larva and space filled with excuter and webin. The damage generally occurs in the upper layers of the grain in bags, bins etc. when the grains are exposed, they are kept in containers which are not full. The damage caused by this pest is more and generally this infestation is common in monsoon month. The adult moths is yellowish / yellowish brown in color with narrow pointed wings having long fringers. The forewings are pale white and hind wings are uniformly grey in color. A single female lays about 120 – 400 eggs in the cracks or cervices on the floor or holes in the grain. At the time of laying the eggs are oval and white, but later turn bright in color and hatch out about 7 days. The young caterpillar penetrates the grain and feeds on the internal contents of the grain for 2 – 3 weeks and pupates in a silken cocoon inside the grain for 7 – 10 days after which, the adult emerges. Usually there are 3 – 4 generations per year and during winter, the caterpillar hibernates. They inflict severe damage to unhusked paddy in addition, they also attack ripening grains of paddy, sorghum etc. in the standing crop and stored grain. Pulse beetle b.n. Callousobruchus chinensis. Family: Bruchidae Order: Coloeptera. It is distributed all over the world and recorded in all parts of India. It is considered to be a minor pest in all other countries but in India, it is a major pest of stored products. (Pulses). The grub causes the damage by feeding on the contents of the pul;ses leaving behind the shell and the adults escape by cutting a round hole in the grain. The infestations start in the field itself and get established in the store houses. The adult beetle is small, chocolate or dark brown in color with abruptly rounded posterior and the antennae are serrated and there are 2 characterisitc white spots near the middle of the body. The eggs are elongate laid singly on the pulses and several eggs are laid on the single pulse grain. A single female lays more than 100 eggs and incubation period is 4 – 7 days. The grubs bore into the pulse and develop

inside and complete their development in 2 – 3 weeks. The grubs are whitish in color, cylindrical in shape, fleshy and strongly wrinkled. Pupation takes place inside the pulse itlsef and lasts for 4 – 28 days depending on the temperature and moisture. During winter, the larvae hibernate and adults come out during march. There are 7 – 8 overlapping generations per year. The adult’s life span is short, lives only for 2 days. It causes severe damage to stored cowpea grams, lub lub niger, soyabeans ,pigeon pea, etc. it is also known to infest red gram pods in the field. INSECT PEST OF RICE 1. rice stem borer 2. rice gall midge 3. brown plant hopper 4. rice ear head bug Rice stem borer or yellow stem borer: b.n. Scirpophaga incertulas. Family: Pyranstidae Order: Lepidoptera. • This insect is found in all rice growing areas of asia, attaching only rice. • Damage is caused by the larva which fed inside the stem causing drying of the central shoot which is referred to as “dead heart” in young plants. • Drying of the panicle without formation of grain in older plants is referred to as “white ear”. • In TN it is found to inflict damage to rice crops during oct – jan to a great extent. • The female moth has bright, yellowish, forewing with a black spot, whereas the male is smaller than the female with no black spots on the fore wings. • The female moth lays 15 – 80 eggs in a mass near the tip of the rice leaf blade and covers them with grayish brown hairs. • A female moth lays 2 – 3 such egg masses in 5 – 8 days, tiny larvae hatch out from the eggs. • The young larvae enters the leaf sheath, feeds for 2 – 3 days and then bore into the stem near te node. • Usually only one larvae is found inside the stem. • The larvae become fully grown in 33 – 41 days and measures about 20 mm in length. • It is white or yellowish and turns into pupa within a silken web inside the stem. • In 6 – 10 days, the adult moth comes out of the stem through a hole which was earlier covred with light silken web by the larva • 3 – 5 broods per year. Control measures: • Egg masses may be collected and destroyed. • At the time of transplantation in the main field, tips of seedlings may be clipped off, helps in removing the egg masses. • Some adults are actively phototactic, light traps may be used to collect and kill the adults. • Spraying of chemicals like Phosphamidon, Chlorphyriphus 2 – 3 times at 15 days of the transplantation is found to be effective. • Application of Phorate 10% or Carbofuran 3% granules to 5 cm of standing water in a rice field 20 days after transplantation. The rice gall midge b.n. Orscohia oryzae Faimly: cecidomiidae Order: Diptera.

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Gall midge is also causing concern to rice growers in certain areas of TN. It is an important pest in Madurai, Tanjore, Ramanathapuram, and Trichy. • It is a pest at the tiller phase and becomes more active on the onset of monsoons. • More activity is seen in mid august to September and November. • The loss on an average is from 30 to 3% and maximum can go up to 80% • Incidence has reduced in the last decade, following the use of yielding varieties, like IR8, IR20, Jaya, and Co33 which are more susceptible. • The insect is popularly known as “Anaikomban” or silken shoot, since its attachment causes the formation of the leaf sheath into a hollow, pink, purple, or pale green cylindrical tube, bearing at its tip, a green reduced leaf blade. • This structure derives after the emergence of the adult fly. • If the tillers attacked when the crop is 35 to 45 days old, panicles are not formed, resulting in heavy loss of yield. • This insect also breeds on other grasses of the rice fields. • The mosquito like adult fly is yellowish brown in color. • The female lays 100 – 200 reddish eggs which are elongated and tubular. • The eggs are laid singly or in groups of 2 – 6 on each leaf blade. In 3 – 4 days, the maggots hatch out. • Only one pale red maggot develops on shoot apex. • Throughout its development for 15 – 20 days it remains inside the tubular gall formed by its feeding activity. • The pupa is formed inside the gall and at the time of adult emergence, in 2 – 8 days it wriggles upto the tip and projects half way out. Control measures. • Dipping of seedlings in the emulsion of 0.02% of Chlorpyriphos for 12 – 14 hours before transplantation protects the crop for 30 days against the midge attack. • Application of phorate 10% or Carbofuran 3% granules, 20 days after transplantation in standing water in the field will minimize the gall midge attack. • Biological control of the pest by larval parasites like Polygnotus spp. And Platygasta is also recommended for large scale control. • Avoiding late planting, growing resistant varieties, removal of alternate hosts like the weeds, use of height traps to trap the adult and avoiding close spacing helps in the control of this pest. The brown plant hopper b.n. Milaparvata lugens Family: Delpharidae Order: Hemiptera. • Once considered a minor pest, but has attained a major pest status level after the introduction of high quality rice varieties. • Serious pest since 1973 on al high yielding varieties in Kerala, TN, AP, WB, UP, MP and Punjab. • The adults and nymphs in large numbers suck the plant sap at the basal part of the tiller causing ‘hoppers burn’ a symptom that causes crying of the leaves. • Severe attack causes lodging and heavy loss in the yield ranging from 10 to 80%. • The adults are brown in color. • Female insect lays 300 – 350 eggs in rows on either side of the midribs of the leaf sheath. • Nymphs hatch out from the eggs in 5 days. • They are wingless and wings develop later.

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The nymphs become adults in 15 days. Adults are of 2 distinct forms. Maeropterous (long wings), brachypterous (short wings) forms. They are also the vector of grassy stunt virus.

Control measures: • Farmers are advised to grow tolerant varieties. • Early plantation with wide spacing will reduce the multiplication of the pest. • Use of high level of nitrogenous fertilizers favors multiplication of the pest and thus be used judiciously. • Once infestation is observed, water from the field should be drained and reduce the pest population. • Natural enemies like predatory bugs, Cayrterhious limidiperious, spiders like Dyeosa pseudoannulata exercise natural control of BPH. • Recently, Mucor spp. has been found to infect BPH. • Dusting BHC 10% or Carabryl 10% towards the base of the tillers is effective in controlling the BPH. • If infestation is observed in the late stages of the crop, spraying of monocrotophos 2ml, quinalphos 2ml and phosolane 2 ml in a liter of water is found to be very effective. The Rice ear head bug b.n. Leptocorisa acuta Family: Coreidae Order: Hemiptera • Insects generally appears before the flowering stage and continuous to the milky stage. • Both adult and nymphs feed on the sap of the peduncle, tender stem and milky grains making them turn chalky. • A female lays 250 – 300 eggs on leaf blade in 10 – 25 gaps. • The incubation period is about 7 days. • Slender grayish nymphs become adults in about 15 days. Control measures: • Dusting BHC 10% or Carbaryl 5% controls the pest. Insect pest of Cholam or Jowar (Sorghum vulgare) Sorghum is the third important crop of India, and is attacked by as many as 150 insect species from the stage of sowing to the stage of harvest, resulting in the loss of yields. • The cholam shoot fly • The cholam stem borer • The ear head bug • The cholam midge. The cholam shoot fly b.n. Aptherygona saccata. Family: Muscidae Order: Dipetra • Serious pests of cholam in India. • Larvae feed on the growing tips and inside the stems of the young plants and cause dead heart. • The seedlings, upto 4 weeks of growth are attacked. • The attack is severe during summer in Coimbatore and during winter in the southern districts.

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The infestation may even go up as high as 86% Female is whitish gray and lays 20 – 25 eggs at a time in the leaf surface of the leaf blade. Eggs are white and cylindrical. Larva hatches out from the egg in 1 – 2 days. It migrates to the upper surface of the leaf and enters the stem between the leaf sheath and the central shoot. During its feeding, the central shoot dies and the tissues in the damaged area start decaying. In 8 – 10 days the larva becomes fully grown and pupates in the soil or in the stem. Adult fly emerges in 8 – 10 days. Total life cycle extends in 17 – 21 days.

Control Measures: • Sowing of sorghum seeds should be done soon after the onset of monsoon, since later sowing suffers heavy attack by the shoot fly. • Application of Phorate 10% granito or Carbofuran 30% granules in furrows at the time of sowing is effective. • Resistant varieties IS 1054, IS 5613, IS 5639, may be grown. 2.) Cholam Stem borer: b.n. Chilo portellus Family: Cucurbidae Order: Lepidoptera. • Month old Cholam crop is attacked by this. • Due to feeding by the larva inside the stem, the central shoot dies resulting in “dead heart”. • Attack is noticed even at the rate stage of the crop. • The moth is straw colored and medium sized. • Female lays 300 scale like, flat, oval eggs overlapping each other in batches on the under surgace of the leaf near the midrib. • Eggs hatch in a week and the larvae bore into the stem. • Larva becomes fanct and grow in 25 to 30 days, yellowish with a brown head and measures about 26 mm in length. • It pupates inside the stem and the adult emerges in a week. • Total life cycle occupies 30 to 40 days. • Pest is active throughout the year. But a larval dis* is noticed during nov-feb in northern india. Control: • Spray application of carboryl or endosulfan thrice at 15 days intervals for one month after sourcing gives protection. 3.)The Ear Head Bug b.n. Calocoris angustatus Family: Miridae Order: Hemiptera • • • • •

Rainfed sorghum crop is savaged by many sucking pests. One such is the ear head bug Pest was first reported from TN in 1891 and is now considered to be a serious pest of cholam in the state. The nymphs and adults suck the sap from the developing mains and then turn them chally. Loss of grain raises from 13 to 30%. Conmpact heads are affected more severely.

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The greenish femal bug insects the light source. Coloured, cigar shaped eggs under the or into the middle of the florets , at the rate of 16 eggs per floret. • Female lays 150 to 200 eggs in a fortnight. • Life cycle from egg to adult occupies 15 days and the insect completes 2 generations on cholam in a year. Control • Dusting of carboryl 10% at 10 days intervals at the milky white stage of the crop controls the pests effectively. • A reduvid bug (reduvidae spp) is predatory on this ear head bug. 4.) The Cholam Midge b.n. Contoarinia sorghicola family: Ceridamyiidae order: Diptera • It is also a important pest of cholam in india. • Maggots feed on the developing grain and cause loss in fluid ranging from 20 to 50% • Orange colored female fly is mosquito like and the female insects lay egg singly into the developing florets. • It lays about 30 to 100 eggs. • Maggots feed inside the developing florets and pupate inside the damaged florets. Adult fly emerges between the tip of the floret leaving the white pupal case attached to the tip of the floret, which is very characteristic of the life cycle. Egg to adult occurs from 14 to 19 days. Control: Spray application of endosulfan or carboryl. Phosalone or dusting of carboryl 10% is useful in controlling the pest.