The Efficacy of Chlorpyrifos on Diamond back Moth Olutella Xylostella, A serious Defoliator of Cabbage in the Plateau Economy of Nigeria

A trial was carried out in 2003 and 2004 dry seasons to test for the efficacy of various concentrations of chlorpyrifos (Termex*R 48N EC) insectide on the insect pests of cabbage for recommendation to farmers. The plots were laid out in a randomized complete block design with three replications in a farmer’s field at Naraguta near Jos in Plateau state. Termex was applied as soil drench plus + foliar spray at four concentrations (0, 25, 50 and 100 1 of water ha) to cabbage. Insect population were monitored at weekly intervals, while the number of damaged cabbage heads and yield were assisted at plant maturity.
Major insect pest observed on cabbage was the diamondback moth Plutella lyostella. The population of the diamondback moth larvae and the number of plants they defoliated were significantly lower in the treated plots than the control. Maximum mean number of 2.4 diamondback moth larvae plant was observed in the treated plots, while up to 6 plant was observed in the control plots. Defoliation increased progressively from the period of head formation till harvest in all the plot except those treated with the highest concentration of Termex (100mo/100 12 of 3ater ha) where no larva was observed. Plots treated with 100ml/100 1 of water ha had significantly higher yields than those of all other concentrations and control, although lower concentrations of Termex also increased yields compared with the untreated control plot.