The efficacy of chlordimeform for the control of the northern fowl mite, Ornithonyssus sylvarium (Canestrini and Fanzago) (Acarina, Dermanyssidae).

Chlordimeform applied as a 0.06% low pressure spray controlled the northern fowl mite (NFM) for at least 90 days. Tetrachlorvinphos applied as a 0.5% low pressure spray was equally effective. Chi square analysis of NFM population estimates indicated that NFM populations on the untreated control birds stayed essentially the same throughout the test, whereas, the NFM populations on both acaricide-treated groups were significantly lowered by the seventh day of the test (P less than .01). Chlordimeform seemed to work more slowly than tetrachlorvinphos in controlling NFM.