Evaluation of Acephate and Dimehypo Against the Bagworm, Dapula (Clania) tertia by Trunk Injection

A field trial was conducted to evaluate the efficacy of two insecticides to control a large species of bagworm, i.e. Dapula (Clania) tertia, by trunk injection. The two insecticides evaluated were acephate (in two formulations, i.e. as a soluble powder and a liquid) and dimehypo (liquid formulation only). Acephate was tested in two rates for soluble powder formulation (7.5 g a.i. and 9.4 g a.i. per palm) and two rates for liquid formulation (6 g a.i. and 8 g a.i. per palm). Dimehypo was also tested at two rates, i.e. 6 g a.i. and 8 g a.i. per palm. Post-treatment assessment of live bagworm larvae population was carried out at 7, 14, 21 and 28 days after the trunk injection treatments. The treatments of acephate soluble powder formulation at 7.5 g a.i. per palm and dimehypo at 6 g a.i. per palm were least effective as these two treatments recorded the highest number of larvae at the end of the trial compared to the other treatments. Liquid formulation of acephate at 6 g a.i. per palm and dimehypo at 8 g a.i. per palm caused some reduction in the population of bagworm larvae, but the desired maximum kill was not achieved. Both soluble powder and liquid formulations of acephate at the rate of 9.4 g a.i. per palm and 8 g a.i. per palm respectively were the best amongst the treatments, and resulted in fast and complete control of the bagworm larvae population at 21 days after treatment. Keywords: Bagworm, Dapula (Clania) tertia, acephate, dimehypo, trunk injection