Correlation of percentage and intensity of CPB attacks on production and loss of products due to various levels of cocoa plantation care

. Aceh Tamiang District is currently developing cocoa plantations. The cocoa plantation management problem is the high attack of Plant Pest Species, especially the Cocoa Pod Borer (CPB), which causes cocoa productivity to decline. This study aimed to determine the percentage and intensity of CPB pests attacks on cocoa plantations. This research was carried out in three sub district in Aceh Tamiang District, Aceh Province. The research location was determined purposively . The selected garden samples had four different care levels: not being treated for, being treated for in moderation, being treated conventionally and practicing IPM. The results showed that CPB pests attacked all of the cacao plantation maintenance criteria. In sequence, the percentage and intensity of CPB pest attacks from the highest to the lowest were found in the criteria for farm care that practiced IPM, were treated conventionally, were treated for and not treated. The farms that were not treated had the highest percentage of attacks and CPB attack intensity. The lowest percentages in the criteria of farms that have been treated with IPM practice. The regression analysis of the relationship between the intensity of the attack and the loss of yield due to the CPB attack. The results showed that the levels of incursions by CPB pests was different depending on the classification level of the plantation The findings highlighted the importance of implementing the practice of IPM to reduce instances of CPB incursion.


Introduction
Aceh Tamiang Regency is currently developing cocoa plantations.The area of cocoa plantations in Aceh Tamiang Regency in 2020 is 1,515 ha, production and productivity are 582 tons and 550 kg/ha, respectively, and the number of cocoa farmers is 3,568 households with a workforce of 1,377 people/year [1].When viewed from the area of the plantation by production, the productivity of cocoa in Aceh Tamiang Regency is still low when compared to the national average cocoa production of 856 kg/ha.
The high attack of Plant Pest Organisms especially Conopomorha cramerella Snellen (Lepidoptera: Gracillariidae) also known as Cacao Pod Borer (CPB) is one of the causes of low cocoa production.In addition to the factor of minimal maintenance of the garden, the application of technology is lacking, and the age of the plants is past its productive period [2].CPB is a pest of cocoa in Indonesia for more than three decades since it was discovered in 1980.This pest is only a threat in Indonesia [3].Conopomorpha cramerella is the main pest that damages cocoa crops, in Southeast Asia, especially in Malaysia, Philippines, Indonesia [4].As a result of high cocoa yield losses due to CPB pest attacks in Indonesia and Malaysia, it has had a major impact on the economic sectors that depend on the cocoa industry.the cocoa industry is currently losing around $500 million each year [5].
The main problem faced in the management of cocoa plantations in Aceh Tamiang Regency is the high CPB pest attack which causes cocoa productivity to decline.Aceh Province's cocoa output remains poor as measured by plantation area under cultivation.Low cocoa production is a classic issue that is still being faced today.This condition is influenced by a high attack of plant pests, especially CPB.In Aceh Province, this pest has the most significant impact on yield loss.An area of 6,858.8ha of cocoa plantations in Aceh Province was seriously affected by pest attacks, while an area of 7,719.6 ha sustained minor damage [6].
Based on the description above, the formulation of the problem in this study is to provide an overview of the existing conditions of CPB pest attacks on smallholder cocoa plantations.The purpose of this study was to determine the Correlation of percentage and intensity of CPB attacks on production and product loss due to various levels of care in cocoa plantations.

Location and time
This research was carried out at three sub district in the Aceh Tamiang Regency they are Manyak Payed Sub District, Bandar Pusaka and Tenggulun.This research was carried out in three sub district in Aceh Tamiang District, Aceh Province.This research was conducted over five months, beginning in Mei and ending in September 2022.

Kind and source of data
The gathered data is in the forms of primary and secondary.Primary data was obtained through the result of field observation and interviews.Interviews are conducted with cocoa farmers at the research locations.Field observation results and interviews were related to the incursion intensity data and loss as a result of CPB pests.As for the secondary data, it was gathered from the literature of other studies as well as information gathered from the Agricultural and Plantation Department of Aceh Province, Statistic Centre Agency of Aceh Tamiang Regency, stakeholders in Aceh Tamiang Regency and cocoa farmer groups at the research location.

Sample location of CPB pest incursion
The sample location to determine the percentage and intensity of CPB pest attack was selected in a garden that has the following criteria: • Untreated gardens (no maintenance, cocoa gardens are in a forest-like condition); • The garden is cared for in moderation (incidental maintenance of the garden, the time is irregular); • Conventional treated farms (cocoa farms are treated with fertilizers, pruning, side grafting of cocoa trees that have passed their productive period and use of pesticides to control plant pests) and; • Farms that have received IPM treatment (have implemented IPM under the guidance of Plantation Service, and Extension Agency in each sub-district.The related offices carry out monitoring regularly).

Analysis method
Samples of cocoa pods attacked by CPB were taken on a 0,5 ha plot of 550 cocoa trees on each garden criteria.From the number of cacao trees (55 stems) planted, up to 10% of the cocoa pods were sampled.The fruit taken as a sample is the fruit to be harvested (ripe).The fruit taken has a homogeneous condition seen from the clones, age, and area of the garden.A sampling of cocoa pods was carried out twice in the harvest season.

Measurement of CPB pest incursion level
To measure the damage level and the loss resulting from CPB incursions on cocoa pods, was conducted according to attack percentage (PS), attack intensity (IS) and loss of result (Y).Attack percentage (PS) indicates the quality of harvested pods, which can be observed from their outer symptoms.This PS calculated by using the pattern as follows [7]: Explanation: P = Percentage of attack (%) a = The number of fruits per tree b = Total fruit per tree Attack Intensity (IS) is the number which describes pod damage levels.Attack intensity is the measurement of CPB utilizing 4 (four) categories based on how many seeds retain their stickiness in each observed pod, that are healthy, light (R), moderate (S), and weight (B).Intensity calculation CPB attack utilized pattern: The scale of CPB pest attack level on cocoa pods gives the weight with the score presented on Table 1.

Loss of cocoa yield due to CPB pests
The determination of cocoa yield loss due to CPB pests using regression with the following mathematical model: Explanation: Ý = loss of cocoa yield (kg/ha) A = constant b = coefficient of variable X X = attack intensity 3 Results and discussions

Pest attack percentage of cocoa pod borer
The various study findings revealed that variations in cocoa plantation management had a major impact on the percentage and intensity of CPB pests.Figure 1 depicts the overall percentage and severity of CPB pest attacks caused by variations in cocoa plantation maintenance levels.Figure 1 indicates that the lowest average percentage and intensity of CPB pests are observed at the level of farm treatment using IPM practices, with 17.87 percent and 6.08 %, respectively.Untreated Farms have the largest percentage and intensity of CPB assaults, averaging 49.33 % and 36.80 %, respectively.The disparity in garden maintenance is believed to contribute to the high percentage and severity of CPB pests.It is assumed that plantations that apply IPM can control CPB attacks better than the level of maintenance of other gardens.Observations in cocoa pods were most affected by secondary branches, while the lowest attack was found on the stem.The fading of the skin color and the presence of green-yellow or red-orange streaks suggest a CPB attack on the cocoa pods sampled.When the cocoa pod is shaken, it makes no sound.Finally, as the fruit is split en open, black seeds that stick together can be seen.As a result of the CPB attack, the comparatively young fruit allows the seeds to adhere to the fruit surface and one another.Ripe fruit, on the other hand, does not harm the seeds but may reduce their quality.
Since farmers have applied successful cultivation techniques in cocoa cultivation, there is a low percentage and severity of CPB pest attacks on cocoa farms that use IPM.The IPM model applied at the research location is pruning, frequent harvesting, sheathing of fruit and exploiting natural enemies.The high percentage and intensity of CPB pests in the untreated cocoa farms are more due to poor farm management, such as incomplete pruning, fertilization that is rarely done by the farmers, setting the spacing between cultivated plants and protective crops that are too tight, and sanitation for the peeled cocoa pods were not buried by the farmers.This situation is very favorable for CPB pests' growth because the farms' humidity rises and the pest development cycle is not disrupted.Efforts must be made to deter CPB attacks in places where CPB pests are present.
One of the factors contributing to high humidity in the research location's cocoa farms, especially those that are not well and improperly cared for, is that farmers do not prune.Generally, the secondary branches at the ends of the branches are blocked by leaves, allowing the compounds released by the cocoa pods to be caught by the CPB female imagoes, active at night for laying eggs.One of the signs that affect an insect's orientation to its host is the chemical compounds that are emitted into the air by the host and the absence of pruning activities, which makes the plants dense and has high humidity where pests develop.
However, synthetic insecticides unwisely can cause various negative impacts on the environment, such as the emergence of resistance and pest resurgence.When insecticides suppress the pest population and eliminate their natural enemies, the pest population and abundance grow faster than when their natural enemies were already present [8].
The use of inappropriate synthetic insecticides can have adverse effects that are greater than the benefits generated.Those adverse effects can be the development of pest resistance, the emergence of secondary pests, environmental contamination [9], and product rejections due to residual problems that surpass the tolerance threshold.The finding of pesticide residues on cocoa beans shipped to Japan signals pesticide residues' presence on Indonesian cocoa beans [10].
The percentage and intensity of CPB pests are lower in plantations that use IPM than those that do not.Integrated pest management practices for insect pest control will

Untreated farm
Sober treated farm significantly improve cocoa yields and prove to be more lucrative than farmer management.Application of IPM is in line with world consumers' demands for environmentally friendly cultivated cocoa products, where IPM practices combined with the use of CPB pest-resistant clones and regular fertilizers are the key to the sustainability of cocoa cultivation.CPB control by pruning, frequent harvesting and wrapping young fruit (fruit length less than 7 cm) can reduce the CPB pest population.This happens because pruning will create farm conditions that are not suitable for developing the CPB population.
From several research results, it was found that the use of natural enemies to control CPB pests was able to reduce the intensity of attacks and increase the productivity and quality of cocoa beans.The results of [11] study showed that the control of CPB pests with Dolichoderus thoracicus (Smith) (biological control agent) found that the average value of the level of damage to cocoa pods gradually decreased to 1.33%.The percentage of good pods averaged more than 75% in each sample taken.The low percentage of CPB pest attack rates and the average level of damage index value proves that D. thoracicus (Smith) is effective as a biological control agent and can reduce the level of CPB pest attack.Application of biocontrol agents Beauveria bassiana and D. thoracicus and pruning cocoa to control CPB pests in cocoa plantations have proven effective in reducing CPB pests and damage to cocoa beans so that they can increase cocoa yields [12].

Cocoa Yield Losses
The regression analysis results to determine the loss of cocoa yield due to CPB attacks based on farm care level are presented in Table 2.The average area of the sample farms observed was 1 Ha, the mean intensity of the CPB attack was 19.94%, and the average production of all farm samples was 405.69 Kg/ Ha/ year.From the results of the regression analysis of the relationship between attack intensity and loss of results due to CPB attacks, it was found that the intercept value (a) = 698.92and the slop value (b) = -14.70so that the linear regression model was Y = 698.92+ (-14.70)X (figure 2).The negative sign in the value of b indicates that the dependent variable goes both ways.A decrease will follow each increase in the independent variable in the dependent variable and vice versa.Every time there is an increase in the CPB attack intensity by 1%, there will be a loss of yield as much as 14.70 kg/ ha.So the amount of yield loss in cocoa cultivation at the research location is Y = 698.92+ (-14.70)19.94, the result is 293.12Kg / ha / year or 72.25%.The equation Y = 698.92+ (-14.70)X based on the F test shows the equation that can be justified (0.02% significance value).The R2 correlation value between the attack intensity and the results was 0.65; that the value of the regression relationship between attack intensity and loss results is strong.The classification of the influence of the X and Y variables is based on the R-value.As for a to test whether the correlation Y = 698.92+ (-14.70)X can be accounted for, then the model that can be tested F with the analysis of variance table model (ANOVA) with a level of 5% (Table 3).Based on Table 4, it can be seen that the value of Fhit> F.0,05 means that the regression model that explains the relationship between X and Y can be accounted for at the 95% confidence level.From the cocoa pods' observations at the research location, it was also seen that CPB pests attacked, causing a decrease in product weight and quality (damaged beans, wrinkled, and dark color on the bean shell).
Observations on cocoa pods attacked by CPB pests revealed that the pods could continue to grow as if there had been no attack, so that the infected pods were no different from healthy cocoa pods.New symptoms appear from the outside after ripe in the harvest season.Affected cocoa pods are slightly orange or pale yellowish, the fruit becomes heavier and when shaken, there is no tapping sound between the bean and the fruit wall.It occurs because of mucus and dirt's appearance on the pulp and damage to the seeds in the fruit.
The average percentage of cocoa yield loss due to CPB pests was obtained in farms that performed IPM due to variations in the lowest farm maintenance requirements.It is believed that the use of IPM to manage CPB pests will reduce the percentage degree of attack and intensity of CPB pests, thus affecting the low loss of cocoa yields at the research location.From field observations that cocoa farms with high production have been applying the PsPSP technique (Frequent harvesting, Pruning, Sanitation and Fertilization).They have this knowledge from attending the Cocoa Integrated Pest Management Field School.The use of the PsPSP technique will significantly improve the productivity of farmers' cocoa plants, resulting in increased production and high-quality cocoa beans.On the other hand, the reduction of cocoa yields is comparatively higher in farms that are not cared for and are cared for in moderation.It happens due to farmers' cocoa farms are usually packed with shrubs and turn into forests, creating an optimal environment for CPB pests to multiply, resulting in high yield losses on both farm criteria.
Pruning activities are carried out twice a year, which aims to remove unproductive branches and avoid overlaps between plant crowns which can be an ideal place for CPB pests to breed.Fertilization activities are carried out at the beginning and end of the rainy season, while the fertilizers used are urea and TSP.The regular harvest is carried out every two weeks to harvest ripe fruit.This regular harvest is carried out when the fruit is ripe early.Then the fruit peels from the harvest, rotten fruit and other crop residues must be immersed in the soil which aims to suppress the CPB pest population and can function to increase soil organic matter.
Efforts that can be made to overcome low cocoa productivity can be done by applying IPM techniques, such as using cocoa clones that are resistant to CPB pests and have high productivity [13].CPB can reduce production by up to 30% and cause damage to about 10% of crops [14].

Conclusions
The lowest percentage and intensity of CPB pests were found at the level of farm care applying IPM practices with an average of 17.87% and 6.08%.The untreated farms had the highest percentage and intensity of CPB attacks with an average of 49.33% and 36.80%.Regression analysis of the relationship between the intensity of the attack and the loss of yield due to the CPB attack found the intercept value (a) = 698,92 and slope value (b) = -14,70, so the linear regression model is Y = 698,92 + (-14,70)X.

Fig. 1 .
Fig. 1.Percentage and Intensity of CPB pest incursion in the cocoa plantation.

Fig. 2 .
Fig. 2. Graph of the influence of the intensity of CPB pests attack on cocoa yield losses.

Table 1 .
The scale of CPB pest attack level.

Table 2 .
Regression analysis of cocoa yield losses based on farm criterions.

Table 3 .
Analysis of variance (ANOVA) of loss in cocoa yields.