Inhibition of larval horn fly development in the manure of bovines fed Dimilin mineral blocks.

Abstract

In field tests, the IGR Dimilin®, [N-(4-chlorophenyl) – N′ – (2,6-difluorobenzoyl) urea] inhibited development of larvae of Haematobia irritans (L.) in feces of bovines that consumed mineral blocks containing 0.1 and 0.05% of Dimilin. Herds given the 0.1 and 0.05% mineral blocks consumed 36.5 and 26.8 mg AI/animal/day, respectively. Residue analysis of manure indicated that horn fly larvae were sensitive to concentrations of 0.13–0.52 ppm of Dimilin in the manure. Also, horn fly bioassay data showed larval development was inhibited 75 and 83% in manure of bovines that consumed the 0.05 and 0.1% mineral blocks, respectively.