ARS | Publication request: Magnitude of the residue analyses in specialty crops from experimental applications of triazole fungicides.

Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 14, 2012
Publication Date: N/A

Technical Abstract: The IR-4 Project conducts the research required for the registration of pest control products on specialty crops such as fruits, vegetables, herbs, and others. The Tifton IR-4 Analytical Laboratory is one of the program’s five regional laboratories that conduct magnitude of the residue analyses on food-use samples that have been treated at known rates at field research sites throughout the United States. The control of plant pathogens relies heavily on the triazole, or conazole, fungicides. Common to this class of compounds is C2H3N3, a five-membered ring of two carbon atoms and three nitrogen atoms. This residue laboratory analyzed plant tissue samples from 91 field trials conducted from 2006 to 2011 that encompassed 12 triazole fungicide/commodity combinations. These fungicides were applied for a diversity of pathogen controls such as various Alternaria and powdery mildew species, brown rot (Monilinia fructicola), southern blight (Sclerotium rolfsii), Cercospora leaf spot, Botrytis cinerea, and other fungal pathogens on horticultural crops including seven annual crops and eight perennial fruit crops. Application techniques included foliar directed, foliar broadcast, post-harvest dip, post-harvest spray, and chemigation. Analyses were conducted for the parent compounds difenoconazole, metconazole, propiconazole, tebuconazole, and tetraconazole. In addition to the parent compound, analyses were conducted for the triazole metabolites 1,2,4-triazole, triazole alanine, and triazole acetic acid. Residues of the parent compounds ranged from none detected at the lowest validated level up to 8 ppm and those of the triazole metabolites ranged from none detected at the lowest validated level up to 2.4 ppm. This data is submitted to the U.S. Environmental Protection Agency for the establishment of a tolerance or maximum residue limit (MRL) for ultimate field use by the growers of specialty crops.