Diflubenzuron residue and persistence on an oak forest after aerial application |
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| Authors: | B.F. Prendergast W.G. Yendol S. Maczuga R.C. Reardon W.H. McLane D.R. Miller |
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| Affiliation: | 1. Pesticide Research Laboratory, Department of Entomology , The Pennsylvania State University , University Park, PA, 16802;2. Navy Disease Vector Ecology and Control Center , Alameda, CA, 94501;3. US Department of Agriculture, Forest Service , National Center of Forest Health Management , Morgantown, WV, 26505;4. US Department of Agriculture , Animal and Plant Health Inspection Service , PPQ, Otis, ANGB, MA, 02542;5. Department of Natural Resources Management and Engineering , University of Connecticut , Storrs, CT, 06269 |
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| Abstract: | ![]()
Abstract A twenty hectare forest block in central Pennsylvania was aerially sprayed with diflubenzuron (Dimilin 25W®) at the dose of 33.23g A.I./ha in 9.4 litres/ha. Leaf samples were collected from the upper and lower canopies of 27 oaks and understory within this block on the day of spray, May 29, 1991. Canopy leaves were also collected on May 31, June 10, July 29 and September 26, 1991. Recovery of diflubenzuron residues on fortified canopy‐leaf and litter‐leaf samples using analytical techniques employed in this study averaged 87.4% (SE = 7.5%) and 66.2% (SE = 8.2%), respectively. On the day of spray, diflubenzuron residues on the upper canopy, lower canopy and understory averaged 81.18, 39.65 and 8.35 ng/cm2, respectively. Diflubenzuron residues on canopy‐leaf samples collected 2, 12, 61 and 120 days post‐spray averaged 14.83 (SE = 10.19), 16.75 (SE = 9.95), 12.84 (SE = 8.25) and 11.20 (SE = 7.52) ng/cm2, respectively. Diflubenzuron residues on litter‐leaf samples collected after leaf senescence ‐ 169 and 323 days post spray contained measurable amounts of diflubenzuron in 51 and 59% of the samples, respectively. Of the samples with measurable amounts of diflubenzuron, residues averaged 1.36 (SE = 2.44) and 0.65 ng/cm2 (SE = 0.73) respectively. |
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| Keywords: | diflubenzuron aerial application Dimilin 25W |
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