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Bee Mite Resistance to Pesticides
By Ben Hardin
March 13, 2001
Farmers have long known about insect
resistance to chemicals. In recent years, U.S. beekeepers have discovered the
same problem when it comes to controlling bee mites.
Over the last decade, the honeybee-attacking varroa mite has developed
resistance to the pyrethroid pesticide fluvalinate. That has spurred interest
in alternative chemical controls for the mite, the number one pest of U.S.
But finding alternatives can be costly. Agricultural Research Service (ARS) studies
on toxicities of anti-mite compounds could help prevent future wasteful outlays
of research dollars on development of pesticides most likely to soon become
For example, recent research points to futility in considering the formerly
registered acaricide amitraz as an alternative for varroa mite control.
Scientists at the Kika De La Garza
Subtropical Agricultural Research Center, Weslaco, Texas, have found that
resistance to fluvalinate commonly goes hand-in-hand with resistance to
amitraz. Chemically, fluvalinate and amitraz arent related, but mite
detoxifying enzymes may render both ineffective.
On a positive note, ARS research at Weslaco does show that
fluvalinate-resistant varroa mites become significantly less resistant after a
two-year hiatus from treatments.
The Weslaco scientists are seeking alternatives to extensive use of less
environmentally friendly pesticides such as coumaphos, an organophosphate. For
example, the scientists are researching the biology of fluvalinate-resistant
varroa mites, hoping to find ways to survey mite populations for lack of
resistance so coumaphos treatments can often be avoided.
By late last year, the U.S. Environmental
Protection Agency (EPA) had approved exemption labels in 45 states to allow
strictly controlled use of plastic strips impregnated with coumaphos to control
varroa mite and another pest, the small hive beetle Aethina
Honey bees provide a $14.6 billion annual benefit to U.S. agriculture.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.
Scientific contact: Patti J. Elzen, ARS Beneficial Insects Research
Unit, Weslaco, Texas; phone (956) 969-5012, fax (956) 969-5033,