Abstract

Tetranychus urticae and Heliothis virescens are major pests of cotton and have been managed by the indiscriminate use of acaricides and insecticides. The combined use of chemical and biological products, in particular Bacillus thuringiensis-based products, and the rotation of active ingredients can reduce the negative effects of pesticides and can contribute to the management of resistance, control costs, and help the environment. Therefore, research on the compatibility of control tactics is essential to successful integrated pest management (IPM). The objective of this research was to determine the compatibility of chemical pesticides and a B. thuringiensis-based product in the control of T. urticae and H. virescens in cotton fields. Spiromesifen was compatible with B. thuringiensis var. kurstaki. However, it reduced the development of B. thuringiensis by 40 to 65% relative to the control. Bifenthrin was toxic or moderately toxic to B. thuringiensis depending on the concentration used. Compared to the control, the vegetative growth of B. thuringiensis was 20% lower when used with bifenthrin. Bifenthrin + carbosulfan was highly toxic to B. thuringiensis, decreasing its vegetative growth to less than 1% compared to the control. Spiromesifen was compatible with the recommended concentrations of B. thuringiensis var. kurstaki.

Key words: Integrated pest management, management of resistance, pesticides, entomopathogenic bacterium, association of control tactics.