Progress on control of northern fowl mites on caged laying hens.

Recent research on methods for controlling the northern fowl mite (NFM) on caged laying hens is reviewed. On inanimate objects, NFM may be controlled by fumigation with methyl bromide, increased temperature (49 degrees C for 1 h), or decreased temperature (-20 degrees C for 5 days). dipping chickens in aqueous suspensions of carbaryl or stirofos controlled NFM for 6 weeks without exceeding current egg tolerance residues. Feeding chickens reasonable concentrations of systemic pesticides registered for use on dairy cattle in the U.S.A., registered anticoccidials, zinc bacitracin, avermectins, and diflubenzuron did not produce systemic control of NFM. Chickens do develop immunity to NFM. The potential for further development and adoption of these techniques should provide the poultry industry with effective alternatives to existing chemical sprays and dusts.