Diaprepes abbreviatus: Fate of Diflubenzuron and Effect on Nontarget Pests and Beneficial Species after Application to Citrus for Weevil Control13

Abstract

When IGR diflubenzuron, 25W, was applied aerially to a commercial citrus grove for control of Diaprepes abbreviatus (L.), residues in ppm on fruit harvested 27 days after the 6th application (350 g AI/ha/application) were: unwashed fruit, 0.34; washed fruit, 0.11; dried pulp, 0.26; peel frit, 0.31; chopped peel, 0.12; and oil, 20.55. No detectable residue (<0.05 ppm) of diflubenzuron was found in finisher pulp, fruit juice, pressed liquor, molasses, prewash or afterwash water, and emulsion water fractions. No residue (<0.05 ppm) of 4-chlorophenylurea or 4-chloroaniline was found in any of the citrus fractions. Also, the total sealed brood in colonies of honey bees, Apis mellifera L., from the check and sprayed groves was not significantly different at 7 months. No detectable residue (<0.05 ppm) of diflubenzuron, 4-chlorophenylurea, or 4-chloroaniline was found in the honey obtained after 8 aerial sprays. Populations of nontarget citrus pests and beneficial species apparently were not affected by the spray program.