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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #404661
Research Project: Healthy, Sustainable Pecan Nut Production

Location: Fruit and Tree Nut Research

Title: Spray coverage from pecan air-blast sprayers as affected by forward speed and application volume

Author
item Bock, Clive
item Cottrell, Ted
item Hotchkiss, Michael

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: 4/26/2023
Publication Date: 6/1/2023
Citation: Bock, C.H., Cottrell, T.E., Hotchkiss, M.W. 2023. Spray coverage from pecan air-blast sprayers as affected by forward speed and application volume. Pecan Grower. 35(3):18-40.

Interpretive Summary:

Technical Abstract: Pecan (Carya illinoinensis) is an important specialty crop in the U.S.A. Several diseases and pests limit production and require frequent pesticide application to ensure yield is not compromised. Scab (caused by Venturia effusa) and aphid-elicited leaf chlorosis (caused by Melanocallis caryaefolia) are examples. In mature-tree pecan orchards, large air-blast sprayers are commonly used to apply the pesticides to control diseases and pests. The spray coverage, deposition and profiles are poorly defined under the range of application scenarios, limiting the recommendations that can be provided to growers to maximize control while minimizing input costs. To explore effects on spray coverage we set up a system (a simple patternator) using a 19-m-tall pole with spray cards to characterize coverage. Spray was applied at 2.4 and 3.2 km/h and 470 L/ha, 940 L/ha, or 1870 L/ha without a volute, and at 2.4 and 3.2 km/h and 470 L/ha or 940 L/ha. Without a volute, application volume affected coverage at heights =17.2 m (higher volumes resulting in more coverage). Speed also had an effect, but less than the volumes tested. Volute use resulted in more spray coverage at >17.2 m compared to non-voluted sprayers. Spray coverage profiles affirmed the rapid decline in coverage with height without a volute. The results may help guide decisions on volute use, spray volume and speed, and spray partitioning to different parts of the canopy to improve spray profile characteristics for applying more uniform spray coverage to mature pecan tree canopies.