Pesticide Accidents in Relation to Weather Conditions

Abstract

Research has shown that it is inadvisable to spray crops during either near-absolute calms or very windy conditions; therefore, we studied weather maps and reports of herbicide accidents to investigate the hypothesis that the strong positive correlation between largescale pressure gradient and wind-speed can be used to facilitate prediction of favourable spraying times in Oklahoma. We gave detailed study to the conditions of 10 May 1977, the date in that year when the most herbicide accidents were reported. Although a relatively large pressure gradient existed, there was only weak wind at the KTVY meteorologically instrumented tower (150 km distant from the area of the accidents). We also searched for a strong relationship between herbicide accidents and the pressure gradient through tabulations of daily gradients and accident reports. Only a slight tendency is shown for accidents to occur on days with larger gradients. Research and significant findings for this study were hampered by a lack of specificity and detail in accident reports.