Assessment of the effect of cocoa mosquito mirid true bug, HelopeltisTheobroma cacao L.) production in Cameroon (Central Africa)

Abstract

The impact of mirid true bugs on cocoa production is widely assessed for Sahlbergella singularis and Distantiella theobroma species in the cocoa growing area in Africa. No study has been focused on the impact of another common mirid species in cocoa farming, such as Helopeltis sp., on the cocoa productivity. Thus, the main objective of this work was to assess the effect of Helopeltis sp. attacks on cocoa productivity of ten genotypes. Observations were made on infested fruits (cherelles, immature and mature fruits) under a randomized experimental field design. A control assay was also used in our investigations. The overall results revealed that only fruits infected by mirids aborted: 80.0% for cherelles and 0.4% for immature fruits. The numbers of aborted fruits were statistically comparable between cocoa genotypes and their rates varied from 60 to 96%. In contrast, ANOVA showed that the feeding lethal punctures of Helopeltis sp. were significantly (p<5%) different between fruits of the tested cocoa genotypes; the mean values ranged from 41.5±5.5 to 76.0±4.6 and were classified in three homogenous groups, with a significant sensitivity of clone/hybrids T79/501, UPA143 x SNK64 and T79/501 x SNK413 compared with clone SNK16. The proposal of including Helopeltis sp. as one of the most important pest in cacaoculture is discussed.

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Keywords: Cocoa genotypes, production, impact, attacks, mirids, Helopeltis sp.