33 



sulfate kills by contact and fumigation. It may cause a 24-hour reduc- 

 tion in egg production and may kill birds if vent i i at ion is inadequate 

 (Bishopp and Wagner, 1931). 

 DDT and 1 indane 



Before their ban due to residue formation, some chlorinated hydro- 

 carbons were tested on poultry for northern fowl mite control. DDT was 

 considered an ineffective control when a 10% dust would not control 

 mites in vivo (Povar, 1946). Lindane (2% EC) gave good results when 

 sprayed on the vent region of chickens (Hansens, 1951), and a 0.2% 

 lindane powder is still recommended for northern fowl mite control on 

 caged exotic birds (Da II et a!., 1964). 

 Ma lath ion 



Malathion was at one time an effective compound for northern fowl 

 mite control. Sprays of 0.25 and 0.5% gave good results at an appli- 

 cation rate of 25 ml per bird (Hoffman, 1956, I960). Litter treatments 



2 

 of 4% dust at a rate of 0.3 to 0.5 kg per 1.9 m of litter gave good 



results on hens, but severe cases on roosters had to be dusted by hand 



(Harding, 1955). In a more recent test, 4 and 6% dusts, and 0.5 and 



1.0% sprays of malathion were ineffective for mite control; a 25% dust 



gave control for only 3 weeks (Rodriguez and Riehl, 1963). Foulk and 



Matthysse ( 1 963 ) found malathion to be ineffective and suggested that 



mites may be showing some resistance to the compound. Perhaps the first 



northern fowl mite resistance to malathion in the East was found in 



laboratory and field studies by Hall et al. (1978). Nelscn and Bern.:n 



(1965) synergized malathion with triethyl t r i th iophosphate (ethyl DEF) 



and increased its toxicity 12.9 times. 



