Field Activity of Three Mixture Levels of Plant Extract Formulations for the Management of Post-Flowering Insect Pests of Cowpea, Vigna unguiculata (L.) Walp–The Flower Thrips, Megalurothrips sjostedti (Trybom)

Abstract

ABSTRACT Insecticidal attributes of aqueous extracts of West African black pepper (Piper guineense Schum and Thonn) seeds mixed at three proportional levels (10:10, 10:20, and 20:10% w/v) with neem (Azadirachta indica A. Juss) seeds, African pepper (Xylopia aethiopica (Dunal) A. Rich.) pods, garlic (Allium sativum L.) bulbs and clove (Syzigium aromaticum (L.) Merr. & Perr.) inflorescence, were evaluated against the flower thrips, Megalurothrips sjostedti Tryb. in two-year field trials. Compared with the other mixture treatments, the mixtures of West African black pepper with garlic bulb at 10:10% and 20:10% w/v were superior (P < 0.05) in reducing the numbers of M. sjostedti in cowpea flowers during the periods. Pod density was significantly (P < 0.05) higher at these mixture proportions compared with the other P. guineense mixtures and was comparable to cypermethrin + dimethoate used as synthetic check. All the plant extracts at different mixture proportions were superior to the untreated control in all the parameters considered. This result indicates the potential of incorporating P. guineense extract in mixtures with other plant species in the management of M. sjostedti on cowpea flowers to ensure optimum pod load of cowpea.