Droplet Size Effect on Herbicide Used in Cereals to Control Dicotyledonous Weeds

Abstract

Experiments were conducted to evaluate the effect of droplet size on the efficacy of translocated and non-translocated herbicides. Translocated and non-translocated herbicides provided similar control when comparing droplet size effect on efficacy. Medium and very coarse droplet sizes gave the greatest visible injury whereas coarse-sized gave the lowest visible injury assessments for most species. However, droplet size generally did not affect contact herbicide efficacy. Overall, droplet size was not a strong factor contributing to herbicide efficacy and often, differences were only between herbicides. Non-ionic surfactant solutions measured by a Sympatec droplet analysis system gave the highest percent of volume in droplets <150μm compared to other adjuvants. The lowest percent of volume in droplets <150μm was a 0.5x rate. A liquid herbicide formulation gave the largest percent of volume in droplets <150μm whereas an emulsifiable concentrate formulation was lowest. Percent volume in droplets <150μm was often related to the solution VMD.