DDT for the control of goat lice.

Dipping tests with DDT for the control of three species of goat lice, two Mallophaga and one Anoplum, were conducted at Menard, Tex. Angora goats infested with the yellow louse, Trichodedes lzermsi Kellogg and Nakayama, and the red lice, T. Cf/prae Gurlt and T. limbatus Gervais, were dipped in 0.3 and 0.6 per cent of the cbemical in a water emulsion. In every case all the lice were killed soon after hatching. The animals were examined at intervals for ~6 days and no reinfestation developed. In another test Angora goats infestcd with the blue Linognathus stenopsis (Burm.), as well as with yellow and red lice, were dipped in water emulsions in strengths of 0.3, 0.15, 0.07, and 0.04 per cent of DDT. All concentrations killed all red and yellow lice. All blue lice were killed with all concentrations except the 0.04 per cent DDT. The treated animals were examined at intervals for !l5 days, and there was no evidence of a reinfestation. Tests were also made with DDT combined with wettable sulfur in the dips. These tests suggest that neither chemical the effectiveness of the other. The limited tests conducted on Angora goats indicate that a single dipping in DDT may serve as an effec\:ive control for goat lice. The biting lice are more susceptible to this chemical than are the sucking lice. The DDT, even in concentrated emulsions, apparently had no effect upon the fiber or skin of the animals.