colonies/apiaries screened for pesticides. The USDA (US bee LD50 = 0.2 µg/bee, which is ‘highly toxic’. Further, if
Department of Agriculture), National Science Laboratory in 100 µg of the sticker PBO (piperonyl butoxide) is added to
Gastonia, NC, will do the analysis for either the two the formulation, the honey bee LD50 is further enhanced to
miticides (coumaphos and fluvalinate) or a screening of 0.00964 µg/bee which is ‘highly toxic’.
up to 171 pesticides at or near the ppb level. This
laboratory, a part of the USDA’s Agriculture Marketing Beekeepers have been largely unaware of the increased
Service (AMS), currently runs a program to collect samples toxicity of the base pesticide used to formulate their
and analyze pesticide residue levels in agricultural varroa mite treatment of choice (see Frazier, et al, 2008,
commodities, including honey. These data are confidential American Bee Journal, for this information).
and the property of the contractor WHAT CAN BE DONE?
The CCD Task Force, consisting of researchers from several INCREASED TOXICITY
Universities (including the University of Delaware), the
Interestingly the ‘relatively non-toxic’ compound USDA and State Agriculture Departments, is preparing
fluvalinate, incorporated into Apistan® strips for easy information on warning signs and what beekeepers might
insertion into a colony, has been changed with an do to reduce loss impacts. When available, the current
alteration of its relative potential interaction with honey posted recommendations will be updated on the
bees. The initial US Environmental Protection Agency (EPA) MAAREC.psu.edu
website, tentatively by next spring. For
licensing material indicated a honey bee LD50 (the level at now the recommendations are:
which the compound kills 50% of the sample of bees) of
65.85 µg/bee, earning the label ‘relatively non-toxic’. In u Feed Fumagillin to control Nosema.
1990–1994, racemic fluvalinate was replaced by u Control any bacterial infections.
tau-fluvalinate, resulting in a two-fold increase in toxicity.
u Control varroa using IPM techniques.In 1992, the EPA submission was amended. The new honey
u Do not reuse dead-out equipment right away; let itbee LD50 = 8.78 µg/bee, earned a ‘moderately toxic’ label.
‘air out’ for several weeks before placing it ontoIn the 2005, the EPA Bee Ecotox Database listed the honey
u Do not exchange equipment between beekeepers or
apiaries in so far as possible.
u Feed syrup and pollen in times of dearth or other
u Replace brood nest combs with new foundation so
that combs are not reused over periods of years
u Participate in loss surveys.
I still lack an explanation of what caused such a heavy
loss in the University of Delaware apiary that spring and
so I continue, as do many others, to search for ‘answers’.
You would think that 40 years experience might mean
that I had ‘seen it all’. Such is the lore and uniqueness of
bee colony stewardship that I still have much to learn. n
Dewey M. Caron, Dept
Entomology & Wildlife
Ecology, 250 Townsend
University of Delaware,
Newark, DE 19716.
Tel: 302 353-9914 (cell);
(Dewey's lecture was
sponsored by Agri-Nova
Page 18 Bee Craft America January 2009
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