Determining Pesticide Dislodgeable Foliar Residues and Their Persistence Following Application to Tall Fescue lawn Turf
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Date
2007-09-17
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Abstract
Dislodgeable foliar residues (DFR) can be a primary route for human exposure following pesticide application to turfgrass areas. Consequently, a significant portion of applied pesticide may be available for human exposure via dislodgeable residues. In this study, DFR were determined over a 15-day-period following application of the broadleaf weed herbicide carfentrazone (Ethyl alpha, 2-Dichloro-3-[2-chloro-4-fluoro-5-[4-(difluoromethyl)-4, 5-dihydro-3-methyl-5-oxo-1H-1, 2, 4-triazol-1-yl]-4-fluorobenzenepropanoate ), the pre-emergent herbicide prodiamine (5-dipropylamino-α,α,α-trifluoro-4,6-dinitro-o-toluidine or 2,6-dinitro-N1,N1-dipropyl-4-trifluoromethyl-m-phenylenediamine ) and the insecticide bifenthrin (2-methylbiphenyl-3-ylmethyl (1RS,3RS)-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-di-methylcyclopropanecarboxylate) to a mature stand of 'Confederate' Tall Fescue (Festuca arundinacea Schreb). Dislodgeable foliar residues were determined by wiping treated turfgrass with a distilled-water-dampened cheesecloth and analyzing samples using gas chromatography⁄ mass spectrometry (GC/MS). Less than 20% of the total applied carfentrazone was dislodged with 14% of DFR occurring immediately after application and a total of 6% for the remainder of the 15-day study. Prodiamine DFR averaged 80% over the 11-day study with dislodgeable residue levels ranging from a maximum of 17% of the total applied chemical 8 hours after treatment to a low of 4% 11 days after treatment. Approximately 35% of the total applied bifenthrin was available to be dislodged over 15-day study with 34% DFR loss occurring immediately after application and a total of 1% for the remainder of the sampling periods. If pesticides are allowed to dry on the leaf surface, shortly after application carfentrazone, prodiamine and bifenthrin pose minimal risk to human health via dermal exposure when applied at the labeled rate.
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dislodgeable foliar residues, prodiamine, bifenthrin, tall fescue turf, pesticide dissipation, hazard quotients, carfentrazone
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Degree
MS
Discipline
Agronomy
