Pigmy or red pepper mites are one of the pests associated with
commercial mushroom production. These mites belong to the family
Pyemotidae and are found on the sporocarps of mushrooms (Fig. 1)
and on the casing soil in the mushroom beds. The mites occur as
contaminants in canned mushrooms and in mushroom soups. Mushroom
pickers report that pigmy mites cause allergic reactions.
The taxonomy of mushroom-infesting pyemotid mites has become
confused. There is evidence of synonomy and incomplete descriptions.
There has been no extensive survey of the mites on mushrooms in the
United States and a key is lacking for the species on mushrooms.
Presently only two pesticides are permitted by the F. D. A.
and U. S. D. A. for direct application to mushroom beds for pest
control. They are malathion and pyrethrum dusts. There is a need
for another pesticide with miticide properties to be used specifically
against pigmy and other mite species. However, many pesticides are
harmful to mushroom production because they either reduce the yield
or blemish the mushrooms. This is especially true of oil based sprays.
This dissertation consists of four manuscripts prepared for
publication. Each paper deals with a specific problem concerning
pyemotid mites. "Observations on Mushroom-Infesting Pyemotid Mites
in the United States," deals with the life history, ecology, taxonomy,
and distribution of pyemotid mites on mushrooms in the United States.
This subdivision of the dissertation deals with the biology of
pyemotid mites and serves as an introduction for the taxonomic papers.