Effect of repeated applications of buprofezin and acephate on soil cellulases, amylase, and invertase.

The impact of repeated applications of buprofezin and acephate, at concentrations ranging from 0.25 to 1.0 kg ha(-1), on activities of cellulases, amylase, and invertase in unamended and nitrogen, phosphorous, and potassium (NPK) fertilizer-amended soil planted with cotton was studied. The nontarget effect of selected insecticides, when applied once, twice, or thrice on soil enzyme activities, was dose-dependent; the activities decreased with increasing concentrations of insecticides. However, there was a rapid decline in activities of enzymes after three repeated applications of insecticides in unamended or NPK-amended soil. Our data clearly suggest that insecticides must be applied judiciously in pest management in order to protect the enzymes largely implicated in soil fertility.