Effects of Selected Plant Materials and Pirimiphos-methyl (Actellic2% D®)on Oviposition by Callosobruchus maculatus (Fab.) [Coleoptera: Bruchidae] and on Organoleptic Properties of Treated and Stored Cowpea [Vigna unguiculata (L.)Walp.].

Abstract

The effects of powdered leaves of siam weed, Chromolaena odorata (L.) King and Robinson; lemon grass, Cymbopogon citratus (DC.) Staph; pitanga cherry, Eugenia uniflora L.; mango, Mangifera indica L.; bitter gourd, Mormodica charantia L. and basil, Ocimum gratissimum L;seeds of horse radish, Moringa ole ifera Lam., and brown pepper, Piper guineense Schum and Thonn; and barks of cashew, Anacardium occidentale L. and mahogany, Khaya senegalensis (Desr.) A. Juss., on oviposition by cowpea seed bruchid, C. maeulatus (Fab.) and on the organoleptic properties of treated cowpea [Vigna unguiculata (L.) Walp.] seeds were evaluated under ambient laboratory condition. A pirimiphos-methyl (Actellic 2%D®) treatment and an untreated control were included for comparison. The plant materials were tested at the rates of 2.5, 5.0 and 10.0 g/100 g while pirimiphos-methyl was tested at 1.0, 2.0 and 3.0 g!l 00 g seeds of cowpea in a factorial experiment. The number of eggs laid and the number of seeds with eggs were counted in a random sample of 10 seeds at day 7 postinfestation. The untreated control had 2.9-8.2 eggs/seed and 9.7-10.0 infested seeds over the 6 months storage. Relative to this, 1.0 g pirimiphos-methyl/100 g seed (with 0.2-0.7egg/seed and 1.0-5.7 infested seeds), 5.0 g seed powder of P guineense/l00 g seed (with 0.3-1.6 eggs/seed and 2.0 7.7 infested seeds) and M. oleifera /100g seed (with 0.7-2.3 eggs/seed and 4.0-8.3 infested seeds) caused significant (P<0.05) reductions. O. gratissimum (with 1.5-5.4 eggs/seed and 5.0-S.7 infested seeds) was effective only at the high rate of 10 g/ 100 g seed. The plant products and pirimiphos-methyl had no significant effect on organoleptic characteristics of the treated and stored cowpea seeds.