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United States Department of Agriculture

Agricultural Research Service

Title: The Impact of Application Variables on the Effectiveness of Nursery Stock Sprays

Authors
item Derksen, Richard
item Krause, Charles
item Fox, Robert
item Brazee, Ross

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: July 19, 1999
Publication Date: N/A

Interpretive Summary: In 1996, the nursery/landscape industry generated nearly $50 billion in consumer sales. Consumer demand is requiring the nursery industry to increase production while maintaining tighter controls over production techniques, especially those related to environmental stewardship. Keeping in mind the nursery industry's needs to improve the efficiency of application techniques and to minimize its impact on the environment, a series of experiments were designed to evaluate the effect of several different application parameters on the fate of nursery tree sprays. An experimental cross-flow (CF) fan sprayer and a conventional, air blast type of sprayer (DW) were used to treat multiple rows of four year old, multi-stem, red maple trees, and Turkish Filbert trees. Besides sprayer type, application rate, travel speed, air-assist fan speed, and fan orientation were evaluated. Food coloring applied by each application type was used to estimate deposits on leaves and ground targets. The test results showed that the conventional DW sprayer produced the highest deposits in the tree row closest to the sprayer. However, there was less variation in spray deposits across canopies for the standard CF treatment. The CF sprayer also produced deposits that covered more of the leaf area than compared to the DW treatment. Slowing the CF fan speed increased deposits in the row closest to the sprayer and reduced spray losses to the ground. Nursery managers can use these results to adjust the operation of their sprayers so that they can keep more spray on target which will reduce the total amount of pesticide needed to provide biological control and will reduce time spent making applications.

Technical Abstract: Concerns regarding the future of pesticide registrations and population of areas surrounding nurseries are forcing nursery managers to reevaluate their pest management strategies. These experiments were designed to evaluate how to keep more spray material on target and reduce losses to the ground. An experimental cross-flow (CF) fan sprayer and a conventional, air blast type of sprayer (DW) were used to treat multiple rows consisting of four year old, multi-stem, red maple trees, and Turkish Filbert trees. Food coloring was used to estimate canopy and ground deposits and water sensitive paper was used to evaluate spray coverage. Variations in deposits and coverage across the canopies were generally smaller for the CF sprayer than the DW sprayer. The DW sprayer produced the highest overall deposits in the first row nearest the sprayer. Reducing the DW sprayer ground speed while maintaining the application rate did not significantly change any of the measures of performance. The CF sprayer treatments produced higher coverage ratings in the second and third rows downwind from the sprayer compared to the DW treatments. These deposit and coverage results indicate that the conventional, air blast treatment is limited to making applications on each side of every treatment row if uniform spray deposits are required. The CF sprayer may not need to be operated down every row depending on the overall deposits and coverage needed. The performance of the reduced application rate CF sprayer also indicates that this sprayer design may provide equivalent or superior biological control compared to the air blast treatment while reducing the time and water requirements necessary to make the application.

Last Modified: 9/21/2014
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