Novel approaches to application and performance assessment of insecticide applications to crop leaves

Uniform and controlled applications of insecticides constitute a fundamental aspect of applied research on performance of insecticides. We describe and evaluate a spraying device made from an artist airbrush and a soda bottle, the "bottle sprayer," which can be used to apply insecticide formulations both under laboratory and field conditions. Using the bottle sprayer in conjunction with quantitative behavioral analysis, it was shown that (1) miticides can significantly affect movement patterns and (2) it is possible to quantify mite repellency to miticides. The combination of controlled sprays to portions of trial arenas and quantification of behavioral responses by individual spider mites may be used to address a wide range of applied questions related to spider mite ecology. We used the bottle sprayer to apply water on water-sensitive cards and used simple image analysis techniques to correlate average reflectance per pixels (quadratic reflectance in blue color band) with water dose applied. Consequently, we were able to propose a method to quantify dose applied based on average color on water-sensitive cards. The spray card analysis based on data generated with the bottle sprayer was used to interpret spray card data obtained from spray applications in a commercial potato, Solanum tuberosum L., field and to discuss the possibility of developing quality control procedures for insecticide applications in field crops.