Proceedings of the Vertebrate Pest Conference

Preliminary information on the effectiveness of trimethacarb as a bird repellent on broadcast seed and ripening crops was obtained during 1982 and 1983 from studies in Haiti, India, the Philippines, Bangladesh, Mali, and the United States. R50 and LD50 determinations for nine pest bird species to cereal crops in these countries indicated birds were not as sensitive to trimethacarb as to the avian repellent methiocarb. Rice and millet seed germination was not inhibited at 0.125 and 0.25% treatment levels. Wheat seed germinated well at treatments of ≤0.5% in Bangladesh. Sorghum seed did not germinate as well at any treatment level. Trimethacarb treatments on broadcast wheat seed in Bangladesh protected exposed seed from bird damage. Field trial demonstrations suggested trimethacarb applications of at least 4 kg a.i./ha to ripening grain are needed to reduce bird damage. Degradation of a 4-kg a.i./ha trimethacarb application on rice and sorghum was rapid with residue levels of 0.10 ppm and 0.68 ppm, respectively, remaining on the seed at harvest. These encouraging results, and the fact that trimethacarb is available in many developing countries, suggest that the chemical should be more extensively evaluated.