Effect of Mulvap 100% EC. (Dichlorvos) Spray Schedules on the Control of Insect Pests and Yield of Cowpea (Vigna Unguiculata L. Walp) in Enugu, Southeastern Nigeria

A field experiment to evaluate the effect of mulvap100%Ec. (Dichlorvos) spray schedules on the control of insect pests, and yield of cowpea (Vigna unguiculata L. Walp) was carried out during the 2016 cropping season at the Faculty of Agriculture and Natural Resources Management Teaching and Research Farm of Enugu State University of Science and Technology Enugu, Southeastern Nigeria, using a randomized complete block design (RCBD) with four treatments replicated five times. There was a significant (P=0.05) effect of mulvap100%Ec. Spray schedules on all the parameters assessed. Mulvap100%Ec. Sprayed every 7 days performed significantly (P=0.05) better than any other insecticide spray schedule in the control of cowpea insect pests, in addition to producing significantly higher pod yield. This was followed by the insecticide sprayed every 14 days, every 21 days and no insecticide sprayed respectively. Plants sprayed with mulvap100%Ec. every 7 days recorded mean number of 0.00 aphids per plant, 2.69% leaf damage by leaf beetles, mean number of 0.64 flower thrips, 0.11 maruca larvae per plant, 0.35% dimpled and shriveled seeds and pod yield of 0.26 tonha-1 , followed by plants sprayed with the insecticide every 14 days that recorded mean number of 13.38 aphids per plant, 3.89% leaf damage by leaf beetles, mean number of 1.89 flower thrips per flower, mean number of 0.57 maruca larvae per flower, 1.89% dimpled and shriveled seeds, and pod yield of 0.13 tonha-1 and lastly plants sprayed with no insecticide that recorded mean number of 23.39 aphids per plant, 5.49% leaf damage by leaf beetles, mean number of 4.94 flower thrips per flower, mean number of 1.41 maruca larvae per flower, 3.81% dimpled and shriveled seeds, and pod yield of 0.11 tonha-1