Effect of cashew (Anacardium occidentale) nut shell stored and fresh extracts on cowpea bruchid, Callosobruchus maculatus (Fabricius.) (Coleoptera: Chrysomelidae)

Anotace: A laboratory study was carried out to evaluate the efficacy of cashew nut shell extract in the control of cowpea bruchid, Callosobruchus maculatus (Fab.) under prevailing laboratory conditions. Fresh ethanolic and stored extract of cashew nut shell served as treatments which were compared with untreated control. Data collected on adult mortality, total number of emerged progeny (adults), number and weight of damaged seeds (seeds with holes) and undamaged seeds (seeds without holes) and percentage seed weight loss, and average number of seeds per 50 g in a container and the data were subjected to a two-way analysis of variance and significant different means were separated using Duncan`s Multiple Range test (DMRT) at 5% level of significance. The results revealed that treated plants generally performed better than the untreated. The different rates of treatment recorded significant differences (P <0.05) in causing adult mortality compared to the untreated control. The different rates of treatment also recorded significant differences (P <0.05) in emergence of F1 adults of each treatment compared to the control. It was also noted that the extract reduced or suppressed the weight loss and grain damage as a result of treatment with the extract compared to the untreated control. However, freshly extract of cashew nut shell recorded the highest adult mortality rate and lowest emergence while control had the lowest mortality rate and highest emergence of the insect. The rates of application were indicative of bioactive characteristics of the extract.