Submitted to: Mid-Atlantic Fruit and Vegetable Convention
Publication Type: Proceedings
Publication Acceptance Date: January 25, 2000
Publication Date: N/A
Technical Abstract: Public concern regarding spray drift is forcing industry regulators and formulators to develop guidelines on how to make low drift applications. ARS research has shown that new, low-drift, venturi-type nozzle technology can significantly reduce drift. Manufacturers also claim that droplets produced by these nozzles also provide good spray coverage because of air inclusion within the droplets. With emphasis on small droplet applications, air-assist and spray charging technology have been shown, in some situations, to improve application efficiency. Various types of air-assist technology are available but there are few guides on how to set air system operating parameters. Metal ion generators can now be added to existing spray equipment with the goal of using electrical charges in the spray solution as a deposition aid. Spray coverage and foliar deposit measurements conducted as part of foliar disease management trials have found that new application technologies can perform better, in some cases, than traditional spraying systems. Venturi-type nozzles reduce spray drift and without reducing foliar deposit levels. However, there was no evidence that this nozzle type provides better coverage than traditional nozzles as measured on tomato leaves. Treating spray water with copper ions, at levels typically used for sanitation, did not improve deposition characteristics compared to non-treated water. Further work with ion generators is necessary to determine if these treatments may enhance pesticide activity that could result in reduced rates of pesticide use. Air-assist applications were found to provide more uniform distribution of material and were the only techniques that provided significant underside leaf coverage.