INSECTICIDAL ACTIVITY OF PIPER GUINEENSE SCHUM AND THONN AND DENNETIA TRIPETALA BAKER AGAINST CALLOSOBRUCHUS MACULATUS (F.) COLEOPTERA;BRUCHIDAF).

Abstract

Fruit powders of Piper gunineense Schum and Thonn, and Dennetia tripetala Baker, were applied as single and mixed dosage rates (0.1, 0.2, 0.3, 0.4 and O.Sg per 20g of cowpea seeds) for the control of Callosobruchus maculatus (F.) under ambient laboratory conditions. The powder applications were of 2121lm, 300~Lm,SOO~lmand 5, lrnrn particle sizes. It was observed hat single do age rates of either P. guineense or D. tripetala applied at the rate ofO.lg or more per 20g of cowpea seeds significantly reduced oviposition and adult emergence of C maculatus when compared with the control. Particle size 212/lm of either powders significantly reduced the number of adults of C maculatus emergiing from eggs laid by the beetle on treated seeds compared to powder of particle size of 1mm but not powders of other particle sizes except SOOllm at 0.1 and 0.2 and 0.3g per 20g of seed rates of application. While the powder mixtures were either of300llm and SOOllm particle size. It was observed that the mixture of P. guineense and D. tripe/ala fruit powders applied at the rate of 0.1 g or more per 20g of cowpea seed significantly reduced oviposition and adult emergence of C maculatus in comparison with the control. The application rate of 0.3 - O.Sg per 20g of seed prevented the emergence of F, adults ofC macula/us from the treated seeds. The application rates of 0.4 and O.Sg per 20g of seed completely inhibited oviposition when the particle size of powder mixture was 300llm. However, it was obvious that the particle sizes of powders P. guineense and D. tripetala enhanced the effectiveness in the control of C macula/us hence, further research is needed for testing the validity of these research findings before its adoption.