Crude benzene hexachloride (gamma-isomer content of about 12 per cent) was found to be highly effective in the field control of the mites Acariscus masoni Ewg. and Eutrombiculaalfred4ugesi (Oud.). Practical eradication was obtained by applying this material as a 3-per cent spray in fuel oil, using about 6 pounds of the crude material per acre, and as a 10-per cent dust in talc, at the rate of 10 pounds per acre. A 12-per cent spray in cyclohexanone dispersed by airplane gave immediate and residual control at dosages of 6 to 13 pounds of benzene hexachioride per acre. Control was nearly complete within an hour and remained so for at least 30 days.
Preliminary field tests indicated that benzene hexachloride is effective against mites largely as a fumigant. This characteristic of the material, which was found to permit good control without uniform coverage, would also appear to adapt it for use against infestations in areas of tall, heavy herbaceous growth.
Acknowledgment is made to E. F. Knipling, formerly in charge of the Orlando, Fla., laboratory, for suggestions regarding this study, and to S. R. Pratt and L. M. Wilee for assistance in field work.