Evaluation of four insecticide formulations for the management of insect pests of cowpea

Abstract

Field trials were conducted in two locations (IAR Research Farm Samaru, Zaria, Kaduna State (Lat.11o 11’N and 7o 38’N) and Wase, in Minjibir local government of Kano State (Lat. 12 100 60.0011 and 8 400 0.0011 E), under rainfed conditions in the northern Guinea Savannah and Sudan Savannah of Nigeria. Each plot consisted of seven ridges (five main ridges and two discard ridges, one on either side of the main ridges) and spaced at 0.75 m apart. Each plot size was 26.25 m2 (gross) and separated by a 1.5 m wide border margin on all sides. Four insecticide formulations: Chlorpyrifos 480 E. C. (Chlorpyrifos 480 g/L E.C), Chlorpyrifos plus (Chlorpyrifos 475 g/L+ Cypermethrin 47.5 g/L), Dimethoate 400 E. C. (Dimethoate 400g/L) Imidacloprid 70WG (Imidacloprid 70 WG.), (each applied at 1.5, 1.0 and 0.5 litre per hectare and 0.5, 1.0 and 1.5 kg/ ha for Imidacloprid), standard check (Cyperdicot) at 1.0 l/ha and an untreated control. All the treatments were replicated three times. The treatments were arranged in a randomized complete block design (RCBD). Population of thrips, Megalurothrips sjostedti Tryb., M. vitrata and C. tomentosicollis were sampled 24 hours before and after each spray for three weeks. All data were analyzed using Analysis of Variance (ANOVA) with SAS package and treatment means separated by Duncan Multiple Range test at 5 % level of significance. The results showed that all the four insecticides effectively reduced the population and infestation of insect pests and reduced flower abortion compared to untreated control.