The use of chlordimeform against northern fowl mites on caged laying hens

Trials were conducted to evaluate the efficiency of chlordimeform (N′-(4-chloro-o-tolyl)-(N,N-dimethylformamidine)) in controlling northern fowl mites on commercial caged laying hens. Chlordimeform (0.03% active ingredient (A.I.)) applied as a high pressure spray was as effective (P < 0.05) as stirofos (2-chloro-1-(2,4,5-tri-chlorophenyl) vinyl dimethyl phosphate) (0.5% A.I.) for 63 days post-treatment. Twenty-one days after treatment, chlordimeform (0.06% A.I.) was shown to be more effective (P < 0.05) than stirofos when applied as a low pressure spray.