Evaluation of Plants Extracts from Capsicum annum and Allium sativum against Aphis craccivora Attacking Cowpea Plant in Kano, Nigeria

The efficacy of Capsicum annum fruits and Allium sativum cloves methanolic crude extracts were evaluated on field for the control of Aphis craccivora attacking cowpea plants. Two cowpea genotypes (IAR-48 and IT97K-499-35) were planted separately in a randomized block design, for a cowpea genotype an experimental plots measured 5m x 3m with 1.5m space between plots was demarcated. The plot contained four subplots each measured 1.67m x 3m and replicated three times, given the total of twelve subplots. Within a subplot are three pairs of ridges (70cm apart) tallied with the three different concentrations (200, 600 and 1000ppm) for the plant extracts treatments application. Plant extract treatments along side with synthetic chemical insecticide (Magic force) as positive control were applied to the subplots using Knapsack sprayer 15 days after sowing. The results showed that the population scores of A. craccivora after treatments application on susceptible genotype IAR-48 was reduced significantly (p <0.05) when compared with untreated control subplot. The least population scores of this insect on genotype IAR-48 was recorded in plants treated with A. sativum at 600ppm concentration level which was effective over positive control (synthetic chemical). The genotype IT97K-499-35 recorded no population aphid in plants treated with A. sativum at 200ppm concentration level which is also effective over the positive control. There is critical need to enhance the use of plant extracts scientifically on field as part of Integrated Pests Management for safe food production.