Aldicarb Residue Persistence in Leaf Terminals of ‘Florunner’ Peanut

Abstract

Uptake and persistence of aldicarb residues were measured in five sequential plantings of ‘Florunner’ peanut, after in-furrow application of aldicarb (1.12 kg [AI]/ha). Gas chromatography was used to determine total toxic aldicarb residues (aldicarb + aldicarb sulfoxide + aldicarb sulfone) in terminal leaf buds from plant emergence until 10 wk after emergence. Residue concentrations were extremely high in emerging plants, averaging 2,260-3,405 ppm among plantings. However, residue levels declined rapidly, typically by ≥100-fold every 2 wk, and were nondetectable by 46-62 d after plant emergence. Linear and quadratic regression analysis indicated that residue concentrations in the five plantings fell to 0.1 ppm within 25-35 d of plant emergence. Residues tended to persist less time in successive plantings, apparently because of warmer temperatures and higher plant transpiration rates. Relevance of these data to transmission of tomato spotted wilt virus by thrips, Frankliniella spp., is discussed.