SHORT COMMUNICATION: Influence of time of insecticide application on control of insect pests of cowpea and grain yield of cowpea at Mtwapa, Coastal province of Kenya

African Crop Science Journal,Vol. 4. No. 3, pp. 373-382, 1996 SHORT COMMUNICATION: Influence of time of insecticide application on control of insect pests of cowpea and grain yield of cowpea at Mtwapa, Coastal province of Kenya S. Kyamanywa Code Number: CS96078 Sizes of Files: Text: 24.5K Graphics: Line drawings (gif) - 14K Tables (jpg) 320K Abstract Grain yield of cowpea, the most important grain in the Coast Province of Kenya, is very low mainly because of insect pests attack. It is, however, not clear which growth development stages at which pest attack occurs lead to significant reduction in yields. Consequently, it is difficult to focus control strategies on a particular growth stage. A study was, therefore, conducted to determine the critical stage of cowpea growth at which insecticide application minimises grain yield loss due to pests. The results indicated that controlling flowering and podding pests resulted in 15 fold increase in cowpea grain yield. It is concluded that control efforts should be focused on flowering and podding pests. Key Words: Maruca testulalis, Megalurothrips sjostedti, Ootheca sp., Pod sucking bugs, Vigna unguiculata RESUME Le rendement de grain du niebe, qui est le plus important dans la cote provinciale du Kenya, est surtout plus bas a cause de pestes d'insectes. Cependant, il n'y a plus de precisions sur l'etape de la croissance qui reduit sensiblement le rendement du niebe en cas d'attaque. Par consequent, il est difficile de concentrer sur les strategies des controles sur une etape de croissance particuliere. Cependant, une etude a ete menee pour determiner l'etape critique de la croissance du niebe a laquelle l'application de l'insecticide minimise pois le rendement des grains a cause de perte des pestes. Les resultates ont indique que le controle de croissance des fleurs et de la cosse resultent en 15 fois l'augmentation dans la production des grains du niebe. Il a ete conclu que les efforts des controles devrent etre concentres sur la croissance de fleurs et de la cosse. Mots Cles: Maruca testulalis, Megalurothrips sjostedti, Ootheca sp., sacs pour sucer de la cosse, Vigna unguiculata Copyright 1996 The African Crop Science Societ