Efficacy of spring onion (Allium fistulosum) leaf extract for controlling major field insect pests of cowpea (Vigna unguiculata L.) in the guinea savannah Agroecological zone of Ghana

Abstract

The study was set up at University for Development Studies, Tamale, during the 2017 cropping season to assess the efficacy of spring onion extract for controlling major field insect pests of cowpea. The study was a single factor experiment, laid out in an RCBD with three replications. Treatments used were: T1= water, T2, T3, T4 and T5 were respectively made up of 5%, 10%, 15% and 20% of spring onion extract concentrations, T6= synthetic insecticide. Parameters measured were yield components, total yield, insect pest infestations. The highest grain yield was recorded by synthetic insecticide (3367 kg/ha), followed by 20% and 15% concentrations of spring onion extract, 3037 and 2940 kg/ha respectively. Treatment with water recorded the highest grain yield loss (76.15 %) followed by 5%, 10%, 15% and 20% concentrations of spring onion extract, recording yield losses of 67.83%, 21.80%, 12.68% and 1.10% respectively. This indicates that insect pests are economically important and their control is imperative for yield maximization and sustainable cowpea production.