EFFICACY OF SOME INSECTICIDES AGAINST THE COWPEA APHID, Aphis craccivora Koch INFESTING COWPEA PLANTS AND THEIR ASSOCIATED PREDATORS UNDER LABORATORY AND FIELD CONDITIONS

Abstract

This study was carried out to investigate the efficacy of four insecticides namely, kz oil, thiamethoxam, super- misrona oil and primiphosmethyl on the population of the cowpea aphid, A. craccivora Koch under laboratory and field conditions. Results showed that the mean numbers of the nymph and adult stages were irregularly decreased after treatment with all the examined insecticides. This decreasing lasted till the end of two weeks in case of kz oil, thiamethoxam, super-misrona and primiphosmethyl. The results revealed that primiphosmethyl proved to be the highest effective compound in the first and second seasons. On the other hand, thiamethoxam was the lowest effective one in both seasons. The other tested insecticides occupied intermediate positions between the highest and the lowest compounds. The tested insecticides could be descendingly arranged according to their reduction percentages in population as follows: primiphosmethyl > kz oil > super-misrona oil > thiamethoxam. The toxicity of the tested insecticides against the cowpea aphids under laboratory condations were studied. Results cleared that primiphosmethyl was the most toxic insecticide, whereas thiamethoxam was the lowest one causing 78.91, 83.97 and 50.70, 77.37% reduction in the first and second seasons, respectively. These insecticides, reached their maximum percent reduction in C. undecimpunctata population after the initial time of application. Meanwhile, the highest reduction percentage of C. carnea population was also detected after three days of treatment.