RESUMEN
In two trials at the University poultry farm, two formulations of the synthetic pyrethroid permethrin (Ectiban 5.0% EC and Ectiban .25% Livestock Dust) were compared against carbaryl and amitraz sprays for the control of northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), on caged birds. Under continuous reinfestation pressure, birds treated with dust did not support live mites in the vent region until 7 weeks posttreatment in comparison to 4 weeks with the permethrin 0.5% spray. Initially, both carbaryl (.5%) and amitraz (0.5%) sprays were as effective in controlling mites as the permethrin spray but did not provide protection for as long a period. Individual birds were either had dusted or treated with low pressure sprays.