Evaluation of B-Exotoxin of Bacillus Thumngiensis for the Control of Northern Fowl Mites, 1986

Forty White Leghorn hens were caged individually in a 7.3 × 7.3 m shelter at the Pennsylvania State University Poultry Research Farm. The shelter contained 2 banks of single deck, double row cages (46 × 46 × 30 cm) divided by a 2.3 m aisle, 20 cages/bank. On 22 Jul '85, all 22-week-old hens were infested with northern fowl mites by placing mite-infested feathers into vent feathers of the uninfested hens. Hens were reinfested 3-4 times prior to treatment. Twelve hens with the highest mite population densities were selected and randomly placed into individual cages in one bank of the shelter. All other cages in that bank were emptied. On 22 Jan '86, 6 hens were randomly selected and sprayed with 40 ml of B-Exotoxin (1,000 ppm) with a 250 ml chromotography sprayer into the vent and tail area. The remaining 6 hens were sprayed with 40 ml of distilled water to serve as controls. Mite population density estimates were made weekly for 10 weeks post-treatment with the following visual rating scale: 0 = 0 mites/bird; 1 = 1-2 mites; 2 = 3-9 mites; 3 = 10-31 mites; 4 = 32-99 mites; 5 = 100-315 mites; 6 = 316-999 mites; 7 = 1,000-3,159 mites; 8 = 3,160-9,999 mites; 9 = 10,000-31,586 mites; and 10 = greater than 31,586 mites/bird