Residues in Milk Resulting from Ultra-low-Volume Sprays of Malathion, Methoxychlor, Coumaphos, Ronnel, or Gardona® for Control of the Horn Fly13

No residues were found in samples of milk from dairy Cows treated twice daily for 21 days with I ml of a mist spray of either of 2 concentrations of malathion, coumaphos, or Gardona® (2-chloro-I-(2,4,5-trichlorophenyl)-vinyl dimethyl phosphate). The maximum residues of methoxychlor found were 0.006 ppm from applications of the low concentration (1 %) and 0.010 ppm from applications of the high concentration (2%). The maximum residues of ronnel found were 0.014 ppm for the low concentration (5%) and 0.037 for the high concentration (10%). The lower concentrations of insecticides were about the minimum required to control the horn fly, Haematobia irritans (L.), and the higher concentration was twice this minimum amount.