University of California

A guide to the spider mites of deciduous fruit trees


A. Earl Pritchard
Edward W. Baker

Authors Affiliations

A. Earl Pritchard was Assistant Professor of Entomology and Assistant Entomologist in the Experiment Station, Berkeley; Edward W. Baker was U. S. Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine.

Publication Information

Hilgardia 21(9):253-287. DOI:10.3733/hilg.v21n09p253. February 1952.

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The recent development of highly selective acaricides for spider mite control has made it necessary for the economic entomologist to know the particular species he is dealing with. This report, a guide to the spider mites known to occur on deciduous fruit trees in the United States and Canada, is intended to aid him in making determinations in the field and in the laboratory. Included are a taxonomic key to the species, a field guide, and instructions for sampling, slide preparation, and recognition of diagnostic characters. Of special interest are three new combinations, one new species, four new synonyms, and new information on color forms and seasonal phases of Tetranychus bimaculatus.

The following twelve species of spider mites are treated:

Bryobia praetiosa Koch (p. 259)

Metatetranychus ulmi (Koch) (p. 260)

Paratetranychus newcomeri McGregor (p. 261)

Eotetranychus carpini borealis (Ewing), new combination (p. 261)

Eotetranychus willamettei (McGregor), new combination (p. 263)

Eotetranychus uncatus Garman, new species (p. 263)

Tetranychus pacificus McGregor (p. 265)

Tetranychus mcdanieli McGregor (p. 266)

Tetranychus schoenei McGregor (p. 266)

Tetranychus canadensis (McGregor), new combination (p. 267)

Tetranychus bimaculatus Harvey (p. 268)

Tetranychus atlanticus McGregor (p. 271)

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Pritchard A, Baker E. 1952. A guide to the spider mites of deciduous fruit trees. Hilgardia 21(9):253-287. DOI:10.3733/hilg.v21n09p253
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