Evaluation of phosmet for the control of the common scabies mite on cattle

Thirty-four young range cattle heavily infested with the common scabies mite, Psoroptes ovis, were dipped in phosmet (O,O-dimethyl phosphorodithioate S-ester with N-(mercaptomethyl)phthalimide) in 15 trials. All concentrations from 0.15% to 0.25% that were applied once failed in at least one trial, but all concentrations from 0.075% to 0.20% were successful in eradicating mites when used twice at 7- to 10-day intervals. One single dip tried at 0.30% also was successful. Uninfested yearlings were dipped in 0.30% phosmet without apparent intoxication, but 2-year-old cattle treated in a spray-dip machine at 0.40% active ingredient became depressed and stiff gaited.