Effect of Insecticide on the Agronomic Impact Due to Insect Pests Associated with Solanum Aethiopicum L. (Solanaceae) in the Locality of Nkongoa (Centre Cameroon)

The search for a crop protection strategy against pests led us to research the effect of certain insecticides for peasant use on the African eggplant Solanum aethiopicum (Solanaceae). To this end, we carried out observations in Nkongoa (towards Mfou) on leaves, fruits and stems of S. aethiopicum in two fields previously set up by a farmer and differing by a treatment based on insecticides. The results showed that the damage caused on the leaves is caused by the whiteflies Bemisia tabaci (Aleyrodidae), the aphids Aphis gossypii (Aphididae) and the flea beetles Epithrix sp. (Chrysomelidae) while those caused on fruits and stems are mainly due to the eggplant shoot and fruit borer Leucinodes orbonalis (Pyralidae). The average leaf attack rates of S. aethiopicum due to aphids, whiteflies and flea beetles were higher in the untreated site (11.47±2.88% for A. gossypii; 14.45±2.69 % for Bemisia tabaci and 34.46±4.80% for Epithrix. sp) compared to the site treated with insecticides (4.30±1.33% for A. gossypii; 10.66±2.69% for Bemisia tabaci and 10.84±2.34% for Epithrix sp). This attack rate kept the same dynamic for L. orbonalis on the stems and fruits: high in the untreated site (11.25 ± 3.78% on the fruits and 5.41 ± 2.94% on the stems), compared to the treated site (5.51±1.83% on the fruits and 1.25±0.87% on the stems). The average number of individuals of A. gossypii and B. tabaci per leaf of S. aethiopicum was lower in the treated site (0.32±0.12 individuals/leaf for A. gossypii and 1.72±0 .66 individuals/leaf for B. tabaci) than in the untreated site (3.97±0.75 individuals/leaf for A. gossypii and 7.77±1.29 individuals/leaf for B. tabaci). These results are an asset in the search for possibilities of biorational use of insecticides in the chemical control of eggplant pests.