Effect of some insecticides on leaf growth and leaf infestation by galerucid beetle and grain yield of cowpea (vigna unguiculata l. walp.)

Abstract

In an evaluation of six insecticides cypermethrin (0.007%) resulted in the highest grain yield of cowpea by increasing the number of leaves and reducing the galerucid beetle infestation. This was followed by carbofuran (@ 1.5 kg a. i. / ha) + monocrotophos (0.07%) and carbofuran alone ( @ 1.5 kg a. i. /ha). While a significant ( P < 0.01) positive correlation ( r= 0.94) existed between the number of leaves and grain yield, it was negative ( r=-0.92) between grain yield and beetle infestation. The economic evaluation of the insecticides also proved that cypermethrin was the best (BCR=8.81) followed by carbofuran (BCR=5.57).