Characteristics of Evaporation from Water-based Bacterial Pesticide Droplets
Measurements were conducted to quantify the effect of selected environmental parameters on the evaporation rate from droplets of several commercial formulations of the biological pesticide Bacillus thuringiensis (Bt). Results confirmed the positive relationships of evaporation rate with air temperature and wind speed, and the negative relationship with humidity, but failed to reveal any significant dependence of evaporation on turbulence intensity. Evaporation rates from Bt formulations were essentially the same as those from water droplets until the droplet crystallized. The crystallized droplet size was shown to be a constant proportion of the initial droplet diameter. The general characteristics of evaporation from water and pesticide solutions can be fairly well described by a theoretical model that takes the effect of temperature, humidity, and wind speed into consideration.