Effects of an insect growth regulator on western flower thrips (Frankliniella occidentalis) mortality by Beauveria bassiana insecticide products

The efficacy of single and combined treatments of a Beauveria bassiana mycoinsecticide and low doses of an insect growth regulator were investigated to determine the nature of the interaction between two classes of insecticide. Second instar western flower thrips immatures (Frankliniella occidentalis) were exposed for 7 days to leaf discs of red kidney bean (Phaseolus vulgaris) treated with solutions of B. bassiana mycoinsecticide, Novaluron insect growth regulator, or both. Thrips survival was monitored daily. Statistical analysis of the treatment mortalities showed evidence of an additive interaction, but it is possible that a synergism may occur under alternative experimental conditions.