ABSTRACT

The Study was conducted in the humid rain forest zone of south-eastern Nigeria in two locations viz., Umudike in Abia State, it the Michael Okpara University of Agriculture and Umuagwo in imo State, at the Michael Okpara College of Agriculture, to evaluate the field efficacy of aqueous extracts of seeds of black pepper, Piper guineense Schum & Thonn for the control of some key insect pests of Cowpea, Vigiia iinguiculala (L.) Waip and to assess impact of control on the crop yield. The study which was carried out between September and December, 2004 consisted of concentration study, using the following concentrations of aqueous extracts of P. guineense seeds viz., 1%, 3%, 5%, and 10% and frequency of application study using 5% aqueous extract applied at oncea-week, twice-a-week, thrice-a-week and fortnightly. 'I'he experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications. The results obtained showed that 5% and 10% concentrations of the plant extract were most effective and they significantly (P< 0.05) reduced th population of some key insect pests (Oolhecca mulabilis, Mcgaluro/hrips s/osl cdii (Trybom), (7avigralla tomenlosicolis (Stals), and Nezera viridula (L). pod and seed damage. The results also showed that once-a-week and twice-a-week spray regime significantly (l'< 0.05) reduced [lie population of key insect pests, pod and seed damage. The different concentrations also significantly increased the yield of the crop when compared with the untreated check (control). The synthetic insecticide, Cypermethrin (lOg a.i / ha) incorporated for comparison vas however superior in efficacy to aqueous extracts of P. guineense. P. guineense seed aqueous extracts could he recommended for use by resource- poor- farmers who may not be able to afford synthetic insecticides, for mitigating th attack of some key insect pests of owpea and increasing crop yield