Growth and yield of cowpea (TVX 3236) as influenced by organic phosphorus sources and insect control methods in Ejiba, Nigeria

Abstract

An experiment was carried out in late season of 2015 and early season 2016 at the research site of the Lower Niger River Basin Development Authority, Ejiba, Kogi State of Nigeria to investigate the organic phosphorus effect of insect control methods and different sources on insect population density, growth and yield of cowpea variety TVX 3236. Four insect control methods [dimethoate (Contact insecticide) (2.0l/ha), cypermetrin best (Systemic insecticide) (2.0l/ha), dimethoate (1.0l/ha) + cypermetrin (1.0l/ha) and No insect control] and three organic phosphorus sources [steam bone meal, fish bone meal, chicken manure and control] were considered. The treatments were laid out in a split plot design with three replications. Data were collected on insect population density, growth and yield of cowpea. Unprotected plots had higher damage than insecticide protected plots. Plots with dimethoate combined with cypermetrin had tallest plant, largest leaf area when compared with plots with either dimethoate or cypermetrin alone. Plots with poultry manure application had the tallest plant and largest leaf area when mean data of both years were considered. Insect controlled plots had more nodules that were heavier than the control plots in both years. Higher number of nodules and heavier nodules were produced in plots treated with poultry manure. Yield and yield components of plots treated with either dimethoate or cypermetrin were similar and better than the control plots. Pod length, number of seeds per plant, 1000 grains weight and dry grain yield per hectare were better in plots with chemical insect control whether applied alone or combined. Phosphorus application improved growth and yield characters of cowpea. Poultry manure (30 kg/ha) improved growth and yield of cowpea best. However, plots with combined use of dimethoate and cypermetrin gave highest number of pods per plant (46.90). Cowpea field should be amended with poultry manure as source of phosphorus and cowpea insects should be controlled using both dimethoate and cypermetrin for optimum productivity.