EFFICACY OF SOME PLANT POWDERS AS DRIED SWEET POTATO CHIP PROTECTANTS AGAINST LESSER GRAIN BORER (Rhyzopertha dominica) (Fabricius) (Coleoptera: Bostrichidae)

Abstract

Sweet potato (Ipomoea batatas (L.) Lam.) is one of the most versatile and nutritionally valuable crops globally, ranking seventh in importance for food security. This study evaluated the efficacy of three selected plant powders as protectants for dried sweet potato chips against infestation by Rhyzopertha dominica (Coleoptera: Bostrichidae), a significant storage pest. Plant materials from neem (Azadirachta indica), tamarind (Tamarindus indica), and eucalyptus (Eucalyptus globulus) were processed into fine powders and applied, individually and in combination, at a concentration of 10% (w/w) to dried sweet potato chips. The treatments were assessed for adult mortality, number of live adults, feeding damage, and number of perforated chips over a four-month storage period under ambient conditions (27 ± 2°C, 75 ± 5% RH) using a completely randomized design (CRD) with four replicates. Results revealed significant reductions in insect survival, feeding activity, and damage in treated groups compared to untreated controls. The combination treatment exhibited the highest efficacy, achieving maximum mortality (89.3%) and minimal feeding damage. This study underscores the potential of botanical powders as eco-friendly alternatives to synthetic insecticides in stored-product pest management.