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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Aerial Application Technology Research » Research » Publications at this Location » Publication #328827
Title: Aerially released spray penetration of a tall coniferous canopy

Author
item THISTLE, HAROLD - Forest Service (FS)
item REARDON, RICHARD - Forest Service (FS)
item BONDS, JANE - Bonds Consulting Group
item Fritz, Bradley - Brad
item Hoffmann, Wesley
item KEES, GARY - Forest Service (FS)
item GROB, IAN - Forest Service (FS)
item HEWITT, ANDREW - University Of Queensland
item O'DONNELL, CHRIS - University Of Queensland
item ONKEN, BRADLEY - Forest Service (FS)

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2016
Publication Date: 11/1/2016
Citation: Thistle, H., Reardon, R., Bonds, J., Fritz, B.K., Hoffmann, W.C., Kees, G., Grob, I., Hewitt, A., O'Donnell, C., Onken, B. 2016. Aerially released spray penetration of a tall coniferous canopy. Transactions of the ASABE. 59(5):1221-1231.

Interpretive Summary: Aerial spraying is a critical tool used in protecting Eastern Hemlock from damage caused by Hemlock Woody Adelgid. Scientists with the Aerial Application Technology Research Unit in College Station, TX, and the United States Forest Service in Morgantown, West Virginia in cooperation with other researchers investigated the spray movement within a Hemlock forest canopy and resulting deposition on trees surfaces for control of Hemlock Woody Adelgid. The application methods tested provided for significant deposition of the total applied spray both on the canopy and within hard to reach locations within the canopy. Forest protection applicators can used these optimized application methods to provide for effective control of Woody Adelgid in Hemlock canopies.

Technical Abstract: An aerial spray deposition project was designed to evaluate aerial application to an Eastern Hemlock (Tsuga canadensis) canopy to combat Hemlock Woolly Adelgid (Adelges tsugae). This adelgid offers a difficult target residing in the forest canopy at the nodes of branchlets. The study collected 1680 deposition samples on live and artificial collectors (not including auxiliary studies) positioned to evaluate canopy penetration of spray applied from above canopy by helicopter. The results of the study show that canopy penetration is achieved with 3% to 8% of applied material (corrected for foliar area) deposited on the lowest samplers and 6% to 12% deposited on samplers put in ‘hard to reach’ locations in the mid-canopy. The study also suggests that it might not be necessary to apply as fine a droplet distribution (release DV0.5 values of 87 and 108 µm are used in most of the trials described here) as originally thought to achieve coverage in this deep canopy. A second paper will compare these data to existing models.