>So the overallchances that more than a trivally small percentage of
honeybees (or
> native pollinators) will gather fungicide tainted soybean nectar
> or pollen in the summer months are very small.
>
*
How honey bees could be affected
*
To keep Asian soybean rust from reaching epidemic proportions in North
America, USDA-APHIS is urging soybean growers to follow 'preventative' and
'curative' fungicide application programs. The Ohio State Department of
Plant Pathology proposes that spraying begin at the R1 (early flowering)
stage and end at the R6 (seed set) stage to achieve maximum protection.
Spraying guidelines call for *thorough* coverage of the plant (Ozkan 2005),
which means honey bees will probably come into contact with the fungicides
while working the crop.
There are currently five fungicide products that are registered for use on
Asian soybean rust*, and seven more products which have received Section 18
exemption labels for most states**. The majority of these fungicides are
systemic, meaning they penetrate the waxy cuticle of the leaf and travel
throughout plant tissues, preventing or inhibiting fungal sporulation.
Others are contact poisons, which remain on the outer surface of the plant
and inhibit metabolic processes of the fungi (Butzen et al. 2005). Due to
the target-specific nature of the active ingredients, none of these products
have proven toxicity to honey bees or other beneficial insects in accordance
with LD501 or LC502 standards.
Actually, most fungicides aren t toxic to honey bees in the quantities
ingested or contacted during foraging, but in some cases they have been
shown to deter feeding and cause hypothermia in adult bees (Mussen et al.
2004), and even cause developmental defects in larvae (Vandame and Belzunces
1998). Such consequences are termed 'sublethal,' and are generally ignored
in fast-tracked pesticide registration because they are not directly linked
to mortality. For years, research has shown a correlation between sublethal
effects of pesticides on honey bees and a decline in colony size and health,
but a testing procedure for these effects has not yet been integrated in the
standard protocol. Fortunately, there is a growing interest in the
preservation of feral and managed honey bees, which encourages more
extensive research on factors influencing honey bee behavior, including
sublethal pesticide poisoning.
*
Why bother with soybeans?
*
There is no evidence that honey bees significantly increase soybean
production by aiding pollination (Danka and Villa 2004), but commercial
beekeepers profit from setting hives near monoculture soybean fields. In
Tennessee, for example, it is reported that large quantities of surplus
honey crops have been produced by bees working soybean fields (Hivetool.com
2003). As a marketable commodity, soybean honey ranks high among the nectar
crops. Soybean honey is desirable in both taste and nutritive properties,
and its high antioxidant content makes it an ideal preservative for use in
the food industry (Engseth 1999). To the hobbyist beekeeper, soybean is a
readily available and abundant source of nectar and pollen for their bees,
providing forage from Spring to Fall in warmer climates.
http://www.beeculture.com/storycms/index.cfm?cat=Story&recordID=442
Paul, if bees are making honey from soybeans, my math says that they are
exposed to fungicides to an appreciable amount.
Randy
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