EVALUATION DES PERTES EN STOCK DE GRAINES DE NIEBE TRAITE AU CHAMP AVEC DES EXTRAITS AQUEUX DE PLANTES AU NORD-OUEST DU BENIN

Abstract

The present study allowed evaluating efficacy of five plants’ water extracts with insecticidal and or repellent effects, applied in vegetation against pea beetles, on damages of six cowpea cultivars seeds stocked in gourd and canary with ash. It involved six producers of three villages of the commune of Djougou located in the northwest of Benin. Water extracts were made with Hyptis suaveolens, Azadirachta indica, Manihot esculenta, Thevetia neriifolia and Cymbopogon nardus. The experimental design is the model of Fisher with five repetitions. Collected data are the weight and the number of damaged seeds of cowpea which were observed at 30 days after storage, expressed as the percentage of initial values putted into storage. They were submitted to the two ways, namely cultivar with six levels and water extract with six levels, analysis of variance. Results indicated that the use of water extracts allowed reducing very very significantly (p < 0.0001) pea beetles damages on cowpea seeds. Water extracts of Thevetia neriifolia is the most effective. Cultivar Katché peha was the less attacked, followed by Katché sôwôho and Katché Sénégal. Cultivars Kpodjiguèguè and Katché peha nan soôrii are moderately attacked while Toura pera has been the most attacked. A pest management against cowpea pea beetles based on the using of botanical water extracts and the varietal resistance may be considered.