Proceedings of the Vertebrate Pest Conference

Laboratory studies were conducted to determine an effective DRC-1339 concentration and bait dilution ratio to control pigeons. Treated whole corn baits formulated with Alcolec-s®, corn starch, or corn oil as adhesive agents and 0.25% or 0.37% DRC-1339 diluted 1:5 with untreated corn produced < 10% mortality. DRC-1339 treated whole corn baits (0.25% and 0.37%) diluted 1:0 and formulated with Alcolec-s® produced 20% and 5% mortality, respectively. Whole corn treated with 0.37% DRC-1339, diluted 1:0, and formulated with corn starch produced 68% mortality in laboratory-held pigeons and was selected for further evaluations in field studies to provide efficacy data to the EPA. DRC-1339 residue levels observed in pigeons free-feeding on 0.37% undiluted DRC-1339 treated corn was not detected in breast tissue and only occurred in the gastrointestinal tract of two of five pigeons at 0.06 and 0.19 ppm. DRC-1339 residues observed in pigeons force-fed 21 whole corn kernels treated with 0.37% DRC-1339 (approximately 5 times the LD50 dose) were not detectable after 3 h in breast tissue and 24 h in the gastrointestinal tract. DRC-1339 residues in pigeons gavaged with 58 mg DRC-1339 (over 10 times the LD50 dose) were detectable in the breast muscle of four of nine pigeons at 0.061 to 0.10 ppm. DRC-1339 residues in the gastrointestinal tract ranged from 0.13 to > 17 ppm in eight of nine treated pigeons and was not detectable in the remaining pigeon.