Abstract:
Cowpea (Vigna unguiculata) is a multi-purpose indigenous crop that grows largely in the tropics of sub-Saharan Africa (SSA).
Cowpea is consumed either as a vegetable for the leaves, fresh pods, or grain. Cowpea is regarded as a cheap source of protein to poor resource farmers whose diet largely depends on starchy foods such as millet, sorghum, maize, cassava, and sweet potatoes making it a potential crop to contribute to the alleviation of malnutrition.
The use of environmentally friendly measures to control cowpea weevils (Callosobruchus maculatus), such as natural plant extracts is gaining interest.
The reason being that they are less costly and nonhazardous to human and environment. This study examined the efficacy of Aloe vera (Aloe barbadensis miller) and Papaya (Carica papaya) extracts on cowpea weevils during storage.
The experiment consisted of four treatments (Aloe vera leaf extract 10 g/100 g; (W/W), Papaya leaf extract (10 g/100 g; (W/W)), Actellic dust (Pirimiphos-methy +Permethrin) (0.4 g/100 g) and the untreated control) and two varieties of cowpeas that is Narocowpea2 and Mual19-119. The experimental design was in 2 x4factorial design under Complete Randomized Design (CRD). Each treatment was replicated thrice. Data collected were weevil adult mortality, number of eggs, number of larvae, percentage grain damage, percentage weight loss and percentage germination and emergences.
Among the plant extracts the mortality was significantly high in both Narocowpea2 and Mual19119 cowpea varieties more than 65%compared to the untreated control. The plant extracts in this study markedly reduced the number of eggs 15 and 17, larvae 53 and 94, grain damage 16.9% and 12,1%, emergence and weight loss in both varieties of cowpea during storage. The plant extracts significantly increased the germination percentage of both varieties of cowpeas compared untreated control. The findings of this study therefore suggest that both Aloe vera and Papaya leaf extracts can be an alternative to synthetic chemical insecticides in the control of adult cowpea weevils (Callosobruchus maculatus) during storage. Farmers should always use plant extracts for the control of cow pea weevils during storage as an alternative for synthetic pesticides.
Key words; Cowpea weevils, Narocowpea2, Mual19-119, Aloe vera, Papaya leaf extract, Mortality.
