Effect of the organo-trisiloxane surfactant, Break-Thru S240, on the depth of penetration of insecticides into maize whorls and chemical control of stem borers

Abstract

Chemical control of the stem borers Busseola fusca (Lepidoptera: Noctuidae) and Chilo partellus (Lepidoptera: Pyralidae) is complicated because of cryptic feeding deep inside plant whorls where larvae do not easily come into contact with insecticides. In this study the effect of the organo-siloxane wetter, Break-Thru S240, on insecticide penetration into plant whorls and control of stem borers was evaluated. A greenhouse study was conducted to evaluate the effect of the organo-siloxane on the movement of water into plant whorls. The experimental design was a factorial arrangement with three factors. These were: water volume (equivalent to 40 and 300 l ha−1), dosages rate of Break-Thru (0, 200 and 400 ml ha−1) and the condition of the plant (wet or dry) during spray application. A field experiment was conducted to evaluate the effect of the surfactant on insecticide efficacy against stem borers. Results showed that Break-Thru S240 resulted in a significant increase in the number of wet whorl leaves, penetration of water into plant whorls and overall wetting index compared to control treatments. Results from the field experiment indicated that addition of Break-Thru S240 to an insecticide resulted in increased mortality although this increase was not significant.