A technique for studying the biological efficiency of small droplets of pesticide solutions and a consideration of the implications

Abstract

Abstract A simple bioassay technique is described for small, uniformly‐sized droplets of pesticide solutions obtained by use of a microtip spray nozzle. A soluble fluorescent tracer was added to the spraying solution; droplets of the solution were sprayed on leaf discs and counted under a microscope with the aid of an ultraviolet lamp. The technique was used to study the relationships between the number of drops, their size and the dicofol concentration, on the mortality of Tetranychus urticae eggs. LD 50 values decreased as the drop size was reduced; the concentration of the pesticide also affected the LD 50 values. The technique can be used to study the biological efficiency of ultra‐low volume pesticide formulations in the laboratory.