True Bug (Heteroptera) Impact on Cocoa Fruit Mortality and Productivity

Abstract

The real impact of true bug damage on cocoa pods has never been assessed precisely. We conducted a 2-yr study on 1,080 cocoa trees on 36 farms in Cameroon to assess the contribution of true bugs to fruit mortality and production loss. The cocoa fruiting cycle, fruit mortality, and damage caused by true bugs as well as other pests and diseases were monitored on a weekly basis. True bug damage also was described on 2,500 ripe pods per year. Pod weight, bean number, and bean weight were measured and compared for different degrees and types of damage on the ripe pods. Our results showed that true bugs were the main external cause of young fruit abortion. They reduced the abundance of young fruit by up to 10%. In contrast, although one-third of the ripe pods sampled had true bug lesions, only 4% were moderately to heavily damaged. The mean weight of ripe pods was reduced by 12% when there was medium to heavy damage. While the mean weight of wet beans was reduced significantly (by 3-10%), the number of beans per pod was not changed by damage. Despite the reduction in mean weight, the overall weight of beans for the pods sampled was reduced by <2%. Therefore, our study confirmed the common assumption that the economic impact of true bug damage on mature pods is negligible on cocoa farms in Cameroon. However, true bugs have a significant impact on young fruit mortality.

Assessment of the effect of cocoa mosquito mirid true bug, <i>Helopeltis</I. sp. (Hemiptera: Miridae) on the cocoa (<i>Theobroma cacao</i> L.) production in Cameroon (Central Africa)

“…However, numerically our results discrepancy from those obtained by Yede et al (2012) and Bos et al (2007) in the Indonesian cocoa plantations, where physiological abortions of cherelles, commonly called wilt, caused 50% of the total cocoa productivity losses. This numerical divergence is explained on the one hand by the fact that Bos et al (2007) and Yede et al (2012) conducted their works under different environmental conditions; on the other hand, cocoa genotypes observed by these authors were different from ours. This situation confirms the fact that cocoa varieties have different susceptibility/tolerance/ resistance to mirid infestations (Sounigo et al, 2003;Anikwe et al, 2009;N'Guessan et al, 2008N'Guessan et al, , 2010.…”

“…mature) of fruits to mirid, especially in Helopeltis sp. attacks, and support previous works of Yede et al (2012) carried out in cocoa plantations in the Centre Region of Cameroon, where hexapod infestations induced 4 to 60% abortion of cherelles against none for ripe fruits. However, numerically our results discrepancy from those obtained by Yede et al (2012) and Bos et al (2007) in the Indonesian cocoa plantations, where physiological abortions of cherelles, commonly called wilt, caused 50% of the total cocoa productivity losses.…”

“…attacks, and support previous works of Yede et al (2012) carried out in cocoa plantations in the Centre Region of Cameroon, where hexapod infestations induced 4 to 60% abortion of cherelles against none for ripe fruits. However, numerically our results discrepancy from those obtained by Yede et al (2012) and Bos et al (2007) in the Indonesian cocoa plantations, where physiological abortions of cherelles, commonly called wilt, caused 50% of the total cocoa productivity losses. This numerical divergence is explained on the one hand by the fact that Bos et al (2007) and Yede et al (2012) conducted their works under different environmental conditions; on the other hand, cocoa genotypes observed by these authors were different from ours.…”

“…The evaluation of the aborted fruits was carried out during 15 days for cherelles and immature fruits, and 30 days for mature/ripe ones because of their differential susceptibility to mirid attacks (Yede et al, 2012) and phenologic cycle of fruits (Niemenak et al, 2010). The daily number of aborted fruits per stage, genotype and assay were counted.…”

“…The number of lethal feeding punctures of mirids has been expressed by counting the black spots on the surface of the husk of each aborted fruits per genotype and category. Mirid damages on fruits were characterized by the presence of black spots on their surface (Yede et al, 2012).…”