Chapter 6
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Guidelines and procedures for Latex Stimulation
Introduction Modern rubber plantations employ yield stimulants to increase rubber production. Ethephon or (2- chloroethyl phosponic acid) is currently the most effective latex stimulant and has demonstrated its superior efficiency in the past few decades through tapping research trials. Studies have also shown that response to stimulation is influenced by several factors such as agro-management, planting materials and tapping practices.
1. Pre-Requisite to Latex Stimulation The following conditions should be considered as pre-requisites to rubber stimulation and are applicable to most clones:
Proper manuring program - trees must be properly fertilized following recommendations.
There should be no sign of panel drying or brown bast (BB) especially on the tapping cut.
The trees must be healthy, vigorous and free from any diseases
Trees should manifest good tapping with less wounding on the tapping panel. Bad tapping with severe wounding is not suitable for stimulation
Stimulation should be done only during non-wintering season
The bark must be adequately thick as thin and immature bark especially on renewed panel (BI-1, BI-2, BII-2) will give less response and will prove to be uneconomical for tapping.
2.
Constructing an Annual Program for Latex Stimulation The Production Manager should be required to submit an annual stimulation program following the guidelines of application and frequencies recommended in this manual. This should be prepared at least one year prior to actual application to allow for a thorough review by the Plantation Manager or Tapping consultant.
CAP-PBD Post-Replanting Rubber Manual
47
Guidelines and procedures for Latex Stimulation
The following information should be included in the projections: a) Month to be applied b) Block Number c) Planting Year d) Total trees e) Clone (s) f) Previous years' yield g) Projected yield h) Tapping system used. If new, justification for use i) Other vital information.
3.
Procedure of Ethrel Stimulation 3.1 The basic application methods are: Groove Application Method (Gam) This means that the Ethrel Latex Stimulant (ELS) is applied to the groove with the tree lace removed. One disadvantage with this method is the difficulty in removing the tree lace from trees having thin or sticky tree laces. The ELS dose is measured tree by tree with an eyedropper. Bark Application Method (Bam) Ethrel Latex stimulant (ELS) is applied to lightly scraped bark. The width of the strip is approximately 1.9 cm for monthly application. ELS dose is also measured per tree, using an eyedropper. Panel Application Method (Pam) ELS is applied on renewing bark just above the entire tapping cut. This method is easy and cheap, however, a large area of renewed bark and bigger amount of stimulant may be needed during application.
CAP-PBD Post-Replanting Rubber Manual
48
Guidelines and procedures for Latex Stimulation
Lace Application Method (Lam) ELS is applied into the tapping cut without removing the tree lace. The stimulant must touch the inner section of renewed bark just above the entire tapping cut. This method is the easiest and the most economical method of application. With this method, the stimulant stays partly on the tree lace and partly on the tapping panel. Generally, any method of application will result to a positive response on the yield. The most common yield trend as a result of stimulation is when yield increases in the first one or two weeks following each application. 3.2 Preparing Stimulant Solution Ethrel latex stimulant is sold commercially at 10% active ingredient solution. The mixture of the ELS should be as follows, to reach the desired concentration. Procedure
Desired Concentration
ELS 10%
Water
5.00%
1 part Ethrel
1 part water
3.33%
1 part Ethrel
2 parts water
2.50%
1 part Ethrel
3 parts water
3.3. Application on Tapping Systems 3.3.1. Downward tapping system. ELS is applied onto three points of the tapping cut once at each end and once in the middle by using an eyedropper to give correct dosage, then brushing the ELS on to the cut, to distribute it evenly using a paint brush. The eyedropper should be marked (by paint) to indicate the correct dosage per tree. Once assigned ELS applicators have developed the necessary skills and discipline in ELS application, the use of eyedropper may no longer be necessary.
CAP-PBD Post-Replanting Rubber Manual
49
Guidelines and procedures for Latex Stimulation
3.3.2. Upward tapping system. The bark just above the cut should be scraped before ELS application. ELS is placed on the brush with the use of eyedropper then brushed into the scraped bark. Total ELS applied should be measured by using calibrated eyedropper. The brush should be attached on a long handle to facilitate application. Bark scraping is done with a special tool, which has a guide to follow along the edge of the cut, and a sharp cutting edge about 2 cm wide, which scrapes outer bark, without penetrating deep enough to cause latex to flow. The bark should be scraped the whole length of the tapping cut. Normally, the width of scraped bark depends on tapping frequency. We use different widths for d/3 and d/4 tapping, as follows: d/3 = 25.0 mm/month d/4 = 20.0 mm/month 3.4. Application of Stimulants 3.4.1 ELS is applied to half tasks size on alternate basis. 3.4.2 Ethrel must be applied by a closely controlled gang of workers, who will apply ELS to every tree, line by line, up to the middle section of the task where ELS is due to apply. 3.4.3 Application of ELS during Wintering period must be avoided. It must be remembered that the actual wintering period may vary from time to time and therefore the production in-charge must move the ELS resting dates in accordance with actual wintering period. 3.4.4 The workers applying the Ethrel should have a standard sized containers (e.g. ELS empty containers) which should be sufficient for a known number of trees. The actual amount applied per ½ task should always be checked, to ensure that the dosage per tree is being correctly applied. This cross-checking with the eye dropper is a useful management control tool. CAP-PBD Post-Replanting Rubber Manual
50
Guidelines and procedures for Latex Stimulation
3.4.5 Special care must be taken to avoid spillage. Ethrel is expensive and must not be wasted. The amount of ethephon to be applied per tree should be between 0.5 gm / tree to 1.0 gm / tree/ application. 3.4.6 For d/3 tapping try to apply ELS two days prior to tapping. This gives more time for ELS to work, and also gives management a chance to reapply if a strong rain washed off the ELS, (i.e. if a heavy rain occurs less than 2 hours after ELS application). Table 5: Recommended Frequency of Stimulant Application
4.
Frequency of Stimulation (rounds/year) Tapping Panel
Tapping System
Relative Tapping Intensity
BO-1
BO-2
BI-1
BI-2
½ S d/2
100%
2
3
4-6
6-8
½ S d/3
67%
3
4
4-6
6-8
½ S d/4
50%
4
6
6-8
8-10
½ S d/6
33%
6
8
8-10
8-10
Expected Yield Responses to Stimulant Application The objective of latex stimulation is to ensure uniform and sustained yield response of the rubber trees as it matures. This can be obtained through controlled and judicious stimulation program on a suitable frequency of application consistent with the age and productivity of the crop. Staggered stimulation and periodic rest period from tapping will give more uniform yield for each field. This will help field management lessen the problem of yield fluctuation from the field. The table below indicates yield responses of rubber trees from various age and different tapping panels and concentration of ethepon used. The percentage increase in yield represents significant improvement in production following the stimulation regime using the conventional approach of non-stimulated trees as control.
CAP-PBD Post-Replanting Rubber Manual
51
Guidelines and procedures for Latex Stimulation
Table 6: Expected Yield Responses from Different Ethephon Concentration Panel
Ethepon Concentration
Expected Yield Responses
BO-1
2.5%
10-15%
BO-2
3.3%
15-25%
BI-1
5.0%
25-40%
BI-2
5.0%
45-50%
HQ
5.0% or 10%
> 50%
CAP-PBD Post-Replanting Rubber Manual
52
Introduction Modern rubber plantations employ yield stimulants to increase rubber production. Ethephon or (2- chloroethyl phosponic acid) is currently the most effective latex stimulant and has demonstrated its superior efficiency in the past few decades through tapping research trials. Studies have also shown that response to stimulation is influenced by several factors such as agro-management, planting materials and tapping practices.
1. Pre-Requisite to Latex Stimulation The following conditions should be considered as pre-requisites to rubber stimulation and are applicable to most clones:
Proper manuring program - trees must be properly fertilized following recommendations.
There should be no sign of panel drying or brown bast (BB) especially on the tapping cut.
The trees must be healthy, vigorous and free from any diseases
Trees should manifest good tapping with less wounding on the tapping panel. Bad tapping with severe wounding is not suitable for stimulation
Stimulation should be done only during non-wintering season
The bark must be adequately thick as thin and immature bark especially on renewed panel (BI-1, BI-2, BII-2) will give less response and will prove to be uneconomical for tapping.
2.
Constructing an Annual Program for Latex Stimulation The Production Manager should be required to submit an annual stimulation program following the guidelines of application and frequencies recommended in this manual. This should be prepared at least one year prior to actual application to allow for a thorough review by the Plantation Manager or Tapping consultant.
CAP-PBD Post-Replanting Rubber Manual
47
Guidelines and procedures for Latex Stimulation
The following information should be included in the projections: a) Month to be applied b) Block Number c) Planting Year d) Total trees e) Clone (s) f) Previous years' yield g) Projected yield h) Tapping system used. If new, justification for use i) Other vital information.
3.
Procedure of Ethrel Stimulation 3.1 The basic application methods are: Groove Application Method (Gam) This means that the Ethrel Latex Stimulant (ELS) is applied to the groove with the tree lace removed. One disadvantage with this method is the difficulty in removing the tree lace from trees having thin or sticky tree laces. The ELS dose is measured tree by tree with an eyedropper. Bark Application Method (Bam) Ethrel Latex stimulant (ELS) is applied to lightly scraped bark. The width of the strip is approximately 1.9 cm for monthly application. ELS dose is also measured per tree, using an eyedropper. Panel Application Method (Pam) ELS is applied on renewing bark just above the entire tapping cut. This method is easy and cheap, however, a large area of renewed bark and bigger amount of stimulant may be needed during application.
CAP-PBD Post-Replanting Rubber Manual
48
Guidelines and procedures for Latex Stimulation
Lace Application Method (Lam) ELS is applied into the tapping cut without removing the tree lace. The stimulant must touch the inner section of renewed bark just above the entire tapping cut. This method is the easiest and the most economical method of application. With this method, the stimulant stays partly on the tree lace and partly on the tapping panel. Generally, any method of application will result to a positive response on the yield. The most common yield trend as a result of stimulation is when yield increases in the first one or two weeks following each application. 3.2 Preparing Stimulant Solution Ethrel latex stimulant is sold commercially at 10% active ingredient solution. The mixture of the ELS should be as follows, to reach the desired concentration. Procedure
Desired Concentration
ELS 10%
Water
5.00%
1 part Ethrel
1 part water
3.33%
1 part Ethrel
2 parts water
2.50%
1 part Ethrel
3 parts water
3.3. Application on Tapping Systems 3.3.1. Downward tapping system. ELS is applied onto three points of the tapping cut once at each end and once in the middle by using an eyedropper to give correct dosage, then brushing the ELS on to the cut, to distribute it evenly using a paint brush. The eyedropper should be marked (by paint) to indicate the correct dosage per tree. Once assigned ELS applicators have developed the necessary skills and discipline in ELS application, the use of eyedropper may no longer be necessary.
CAP-PBD Post-Replanting Rubber Manual
49
Guidelines and procedures for Latex Stimulation
3.3.2. Upward tapping system. The bark just above the cut should be scraped before ELS application. ELS is placed on the brush with the use of eyedropper then brushed into the scraped bark. Total ELS applied should be measured by using calibrated eyedropper. The brush should be attached on a long handle to facilitate application. Bark scraping is done with a special tool, which has a guide to follow along the edge of the cut, and a sharp cutting edge about 2 cm wide, which scrapes outer bark, without penetrating deep enough to cause latex to flow. The bark should be scraped the whole length of the tapping cut. Normally, the width of scraped bark depends on tapping frequency. We use different widths for d/3 and d/4 tapping, as follows: d/3 = 25.0 mm/month d/4 = 20.0 mm/month 3.4. Application of Stimulants 3.4.1 ELS is applied to half tasks size on alternate basis. 3.4.2 Ethrel must be applied by a closely controlled gang of workers, who will apply ELS to every tree, line by line, up to the middle section of the task where ELS is due to apply. 3.4.3 Application of ELS during Wintering period must be avoided. It must be remembered that the actual wintering period may vary from time to time and therefore the production in-charge must move the ELS resting dates in accordance with actual wintering period. 3.4.4 The workers applying the Ethrel should have a standard sized containers (e.g. ELS empty containers) which should be sufficient for a known number of trees. The actual amount applied per ½ task should always be checked, to ensure that the dosage per tree is being correctly applied. This cross-checking with the eye dropper is a useful management control tool. CAP-PBD Post-Replanting Rubber Manual
50
Guidelines and procedures for Latex Stimulation
3.4.5 Special care must be taken to avoid spillage. Ethrel is expensive and must not be wasted. The amount of ethephon to be applied per tree should be between 0.5 gm / tree to 1.0 gm / tree/ application. 3.4.6 For d/3 tapping try to apply ELS two days prior to tapping. This gives more time for ELS to work, and also gives management a chance to reapply if a strong rain washed off the ELS, (i.e. if a heavy rain occurs less than 2 hours after ELS application). Table 5: Recommended Frequency of Stimulant Application
4.
Frequency of Stimulation (rounds/year) Tapping Panel
Tapping System
Relative Tapping Intensity
BO-1
BO-2
BI-1
BI-2
½ S d/2
100%
2
3
4-6
6-8
½ S d/3
67%
3
4
4-6
6-8
½ S d/4
50%
4
6
6-8
8-10
½ S d/6
33%
6
8
8-10
8-10
Expected Yield Responses to Stimulant Application The objective of latex stimulation is to ensure uniform and sustained yield response of the rubber trees as it matures. This can be obtained through controlled and judicious stimulation program on a suitable frequency of application consistent with the age and productivity of the crop. Staggered stimulation and periodic rest period from tapping will give more uniform yield for each field. This will help field management lessen the problem of yield fluctuation from the field. The table below indicates yield responses of rubber trees from various age and different tapping panels and concentration of ethepon used. The percentage increase in yield represents significant improvement in production following the stimulation regime using the conventional approach of non-stimulated trees as control.
CAP-PBD Post-Replanting Rubber Manual
51
Guidelines and procedures for Latex Stimulation
Table 6: Expected Yield Responses from Different Ethephon Concentration Panel
Ethepon Concentration
Expected Yield Responses
BO-1
2.5%
10-15%
BO-2
3.3%
15-25%
BI-1
5.0%
25-40%
BI-2
5.0%
45-50%
HQ
5.0% or 10%
> 50%
CAP-PBD Post-Replanting Rubber Manual
52
