28 



parasites causing decreases in egg production; parasite prevention might 

 cost as much as $1.1 million. In Florida, Butler (1979) attributed a 

 $3-7 million loss in poultry profits to the northern fowl mite in 1973. 

 Taxonomy 



Although fowl mites were reported in the literature as early as 

 1824 (Toomey, 1921), the first accepted name, Dermanyssus sylviarum 

 (Canestrini and Fanzago) , was not seen until 1877 (Cameron, 1938). The 

 inability of authors to properly identify the northern fowl mite resulted 

 in the appearance of many synonyms. Several authors have followed this 

 synonymy through the years until the accepted scientific name of the 

 northern fowl mite was changed to Grn-Lthonyssus sylviarum (C.S F.) in 

 1963 (Cameron, 1933; Furman, 19^8; Furman and Radovsky, 1963; Laffoon, 

 1963). 



The northern fowl mite was originally placed in the family 

 Dermanyss idae, but was later separated to the Macronyss idae (James and 

 Harwood, 1969)- For years, 0. sylviarum was confused with another 

 poultry pest, the chicken mite, Dermanyssus gallinae. The two can be 

 distinguished by the shapes of the anal plates and by the shapes of the 

 dorsal shields (Lapage, 1956; Baker et a]., 1956; Weisbroth, 1 960) . 

 Ornithonyssus sylviarum has a teardrop-shaped anal plate and the dorsal 

 shield tapers posteriorly; D. gallinae has a truncate anal plate and the 

 dorsal shield is more rounded posteriorly. The complete morphology of 

 the northern fowl mite is well documented (All red, 1970; Gecrgi, 1 37^ ; 

 Pound and Oliver, 1976; Krantz, 1978). 

 3 ionomi cs 



Wood (1920) and Cleveland (1923) published early works describing 

 the biology and life cycle of the northern fowl mite. Cameron's research 



