Diversity, abundance and incidence of fruit pest insects on three Solanum varieties (Solanaceae) in two agro-ecological zones of Southern Cameroon

摘要

Various species and varieties of the genus Solanum (Solanaceae) are among the most important market crops produced worldwide. They may be considered as multipurpose crops since leaves and/or fruits are eaten fresh or cooked in various dishes. The increase of garden surfaces and the permanence of gardening have induced frequent outbreaks and diversification of pests and cryptogrammic diseases. In order to improve farmer’s capacities in controlling these constraints, the present study assessed diversity, abundance and incidence of fruit pests on Solanum spp. Data collection was conducted in two agroecological zones of southern Cameroon: Okola (Center Region) and Koutaba (Western Region), on three plant varieties from the genus Solanum: Solanum aethiopicum (African scarlet eggplant) with two varieties (jakatu and zong) and Solanum melongena (brinjal eggplant) var. inerme. The study aimed to (1) characterise the community of fruit pests associated with these plant varieties, (2) assess damage due to the main pests and (3) determine their impact on fruit yield. To achieve this, systematic sampling were done by visual observations in experimental gardens set up at the above cited sites. Harvests and incubations of infested fruits allowed identifying 15 insect species, belonging to three orders and 12 families: Lepidopterans with Leucinodes orbonalis, Cryptophlebia leucotreta, Helicoverpa armigera, Chrysodeixis chalcites and Hypolycaena phylippus), Dipterans with Batrocera (Batrocera) dorsalis, Ceratitis (Ceratitis) capitata, Ceratitis (Pterandrus) anonae, Neosilba sp., Atherigona sp. three unidentified species belonging to undetermined genera and Coleopterans with Diplognatha gagates and Formicomus sp.. Among them, H. phyllipus and C. chalcites were absent from Koutaba’s samples. Without site considerations, L. orbonalis was the most abundant with higher incidence on fruit production. At Okola, fruit losses on S. aethiopicum var. jakatu, on S. aethiopicum var. zong and on S. melongena var. inerme were 53.8-76.97, 43.65-61.51 and 29.42-46.61% respectively while at Koutaba, they were 49.51-68.57, 33.41-60.23 and 11.68-30.44%. The present study provided baseline data for integrated pest management strategies of Solanum in Cameroon.