In laboratory bioassay, permethrin LD50 for house fly adults was 

 18.0 ppm. 



Northern fowl mite acaricide bioassays gave LCso's for carbaryl, 



malathion, and permethrin of O.k], 1.70, and 2.9 ppm respectively. 



TM 

 When carbaryl, malathion, and Ravap were applied to hens at rates 



of 0.30, Q.hk, and 0.36% respectively, northern fowl mite control 



approaching 100% was achieved with Ravap in 2 weeks. Adequate control 



was achieved after k to 6 weeks with reappl icat ion of carbaryl and 



malathion. Two synthetic pyrethroids, BW 21Z and SD 43775, applied 



once to floor birds at rates of 0.05% and 0.10% respectively, gave 



100% control of mites for 7 weeks. In production trials when 12 



strains of hens were evaluated for the effects of northern fowl mites 



on egg production, no overall difference in egg production could be 



found due to mite control. However, one strain of hens showed a 



significant increase in egg production of 3-67% due to mite control 



with Ravap. 



The use of the above techniques, individually or in combinations, 



will enable the poultry operator to more efficiently regulate house 



fly populations in and around poultry houses. These techniques will 



also enable him to effectively control northern fowl mites on hens 



and determine whether or not mite populations are affecting hen 



performance. 



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