Cocoa Pod Borer

The cocoa pod borer (CPB) Conopomorpha cramerella (Snellen) is considered to be one of the most serious cocoa pests in South-East Asia and the Pacific, since it not only causes crop loss but also greatly reduces cocoa quality. The spread of this apparently invasive pest species was a major setback for Malaysian cocoa production [1]. 

Although it has been argued that its pest status resulted from more than one new encounter with cocoa by this insect, which is endemic on rambutan and other species, recent research at USDA indicates that CPB in South East Asia is genetically very uniform.

Chemical insecticides became widely adopted as CPB control methods in estates until the 1990s, and when the majority of the South -East Asian production shifted to Sulawesi, they continued to be used by smallholder farmers. Extensive work was done during the Malaysian “CPB crisis” in the 1980s, but there has been an almost complete hiatus in pesticide research and development for well over a decade. 

Since then, agricultural chemistry companies have introduced a number of new molecules, belonging to novel modes of action (MoA) against Lepidoptera, but cocoa is not one of their priority crops for development. Previously, CPB infestations were sprayed with gamma-HCH (BHC) and subsequently endosulfan. As with cocoa mirids, the efficacy of these compounds was partly due to fumigant action, which compensated for inadequacies of application.
 

• Current techniques for applying insecticides: (i) based on the fruiting season so application is avoided during the time of peak harvest, (ii) monitoring so application is dependent on of CPB damage threshold {iii) all year application on a fortnightly basis (24 applications per year) which is reported to be a popular strategy but increases the risk substantially if resistance management is not taken into consideration [2].
• Compounds currently registered in Indonesia (the greatest user of CPB insecticides by far) include: pyrethroids (alpha cypermethrin, beta cyfluthrin, deltamethrin, lambda cyhalothrin, etc.), chlorpyrifos and, most recently, fipronil. Many farmers in Sulawesi, where most cocoa is grown, typically apply insecticides 3-5 times per year [3].
• The biological target has been broadly defined [4] and targeted spraying of pods and the undersides of near- horizontal branches is a preferred method of application for smallholder farmers.
• Ideally, management of this insect would focus on crop sanitation and regular complete harvesting of pods (Rampasan), but the level of labour and supervision required prevents successful implementation in many areas.
• Other effective techniques all involve the use of plastic sleeves to protect pods. Again, this is very labour intensive and unless the plastic is biodegradable, or if there are recycling schemes available, severe litter problems may occur.
• A number of biological approaches have been explored to manage CPB predators, attractants (pheromones), parasitoids and various entomopathogenic fungi but all are at the experimental stage, although many producers do encourage various predatory ant species on farm, which prey on CPB pupae and disrupt the behaviour of the adult moths.