Efficacy of some synthetic insecticides for control of cotton bollworms in northern Ghana

Abstract

Lepidopteran bollworms are a major constraint to increased and sustainable production of cotton in the savanna ecology of Ghana. Studies were conducted at the Experimental Farms of the University for Development Studies, Nyankpala in northern Ghana, during the 2009 cropping season to evaluate the effects of three commonly used insecticide formulations, namely, Betsulfan and Endosulfan (each at 3.2, 3.5 and 3.9 l ha^-1), and Thionex (at 2.3, 2.5 and 2.8 l ha^-1), on the population density and damage incidence of the bollworm complex, and their effects on the yield of cotton. The incidence and abundance of bollworms were significantly (P < 0.05) affected by the different insecticide treatments. Bollworm infestation in all treated plots was significantly reduced. Among the insecticide treatments, Thionex at 2.8 l ha^-1 was the most effective. This was followed by that of Betsulfan at 3.9 l ha^-1, Betsulfan or Endosulfan (each at 3.2 l ha^-1) recorded the highest infestation. Lint seed yield of cotton also increased significantly with increased concentrations of the insecticides, Thionex at 2.8 l ha^-1 and Betsulfan at 3.2 l ha^-1 recorded the highest and lowest yields, respectively. For effective control of cotton bollworms for maximum yield in the ecology, Thionex applied at 2.8 l ha-1 is recommended.

Keywords: Control, cotton bollworms, efficacy, Ghana, synthetic insecticides

African Crop Science Journal, Vol. 20, No. 1, pp. 59 - 66