Mode of Action of Insecticides used for the Control of Apple Sawfly, Hoplocampa testudinea, Klug.

Abstract

Hey and Steer¹ have expressed the belief that nicotine acts mainly as an ovicide when used for controlling apple sawfly, though it is also toxic to the larvæ. They quote, however, other authors who believe that nicotine does not kill the eggs of the sawfly. In an attempt to resolve this conflict of views, ten to fifteen stung blossoms from each of the treatments of a field trial for the control of apple sawfly were examined daily in order to find out at which stage the pest was killed. The treatments, applied in the first post-blossom lime-sulphur spray on May 10, 1949, were as follows: 0.05 per cent nicotine, 0.02, 0.005 and 0.00125 per cent, respectively, parathion (diethyl p-nitrophenyl thion-phosphate).