THE PERSISTENCE OF CERTAIN SOIL INSECTICIDES FOR CONTROL OF THE TUBER FLEA BEETLE, EPITRIX TUBERIS (GENT.), IN THE INTERIOR OF BRITISH COLUMBIA

Abstract

In 1953, dieldrin, aldrin and chlordane were applied to potato plots to control the tuber flea beetle. The insecticides were applied at 1.5, 4 and 10 pounds of toxicant per acre, respectively, and harrowed or rotary-tilled into the soil. Aldrin harrowed and chlordane rotary-tilled into the soil provided satisfactory control (i.e., 80 per cent or more of marketable tubers) in 954 and 1955, whereas dieldrin rotary-tilled and chlordane narrowed into the soil provided less effective but acceptable control (i.e., 70 to 80 per cent of marketable tubers) for the same years. In 1956, all treatments significantly reduced damage but not so from a practical standpoint. In 1957, dieldrin, aldrin and chlordane were applied at one-quarter, one-half and the full 1953 rates to half of the plots treated in 1953 and to previously untreated plots. For all insecticides, increasing the rate of application significantly increased the degree of control; the one-half and full rates continued the above levels of control to 1958. Active residues from each of the insecticides remained in the soil from 1953 to 1958.