Pierre Boris Nsoga Etam, Raymond Joseph Mahob, Yede, Paul Serge Mbenoun Massé, Laurent Baleba, Riccado Feudjio, Mouhamadou Moumbagna Mboutngam, Koga Mang’dobara, Stanislas Raphael Bikay, Charles Félix Bilong Bilong
Cocoa dieback is an emergence disease in cocoa farms in West Africa, due to the synergistic action of Sahlbergella singularis Hagl. and/or Distantiella theobroma (Dist.) and opportunist fungi infestations/infections. Data regarding the involvement of others mirid species as Helopeltis sp., commonly encountered in plantations in Southern Cameroon, on dieback process of cocoa plants remain unknown. Then, we investigated the effect of Helopeltis sp. feeding and associated pathogenic fungi infections on cocoa dieback emergence. Two different infestations (mirids and fine needles) alongside a control, on cocoa branches/twigs of eight genotypes (T79/501×SNK479, UPA143×NA33, T79/501×SNK13, UPA14×SNK64, SNK 7, TIKO 31, Pa 7 and IMC 60), were performed in plantations in order to characterize the cocoa dieback, and identify the associated pathogenic fungi using relevant dichotomous keys. Apart from 20.0% of undetermined species, three pathogenic fungi taxa were inventoried in the study site, namely Lasiodiplodia sp. with the highest occurrence (54.3%), followed by Botryosphaeria sp. (17.4%), then Fusarium sp. (8.3%). Overall, the highest occurrence of pathogenic fungi associated with cocoa dieback disease were obtained on branches infested with mirids (80.0% of the total) compared to those with fine needles (16.0%) and control (4.0%). Our results showed that dieback progression on infested cocoa branches varied amongst cocoa genotypes, mean values ranging from 3.0 ± 1.51 cm for genotype IMC60 (most tolerant) to 10.8 ± 2.16 cm for genotype UPA143×SNK64 (most susceptible). The fungi identified behaved as opportunistic species due to the primary Helopeltis sp. infestations of the host plant leading to dieback. Our findings undoubtedly show the synergistic action of Helopeltis sp. and fungi in cocoa dieback handing out and should be taken into account in Integrated Pest Management (IPM) programs against the targeted cocoa disease.
Theobroma cacao genotypes, neglected true bug Helopeltis sp., synergistic action, opportunistic fungi, infestations/infections, Dieback, IPM
Cite this paper
Pierre Boris Nsoga Etam, Raymond Joseph Mahob, Yede, Paul Serge Mbenoun Massé, Laurent Baleba, Riccado Feudjio, Mouhamadou Moumbagna Mboutngam, Koga Mang’dobara, Stanislas Raphael Bikay, Charles Félix Bilong Bilong. (2023) Field Assessment of Cocoa Dieback Due to the Neglected Mosquito True Bug, Helopeltis sp. (Hemiptera: Miridae) and Associated Pathogenic Fungi Infections in Southern Cameroon. International Journal of Agricultural Science, 8, 325-335