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Saving the Bees

Chemical companies mull treatments to protect both buzzy pollinators and crops

April 19, 2004 | A version of this story appeared in Volume 82, Issue 16

Varroa mites and agricultural practices may explain the declining honeybee population.
Varroa mites and agricultural practices may explain the declining honeybee population.

Crop protection companies are facing down charges from French government authorities that their pesticides are responsible for the serious decline in populations of the humble honeybee, Apis mellifera.

try of Agriculture temporarily suspended the sale of products containing the active ingredient fipronil, and there were also fears raised about the active ingredient imidacloprid.

But a mustering of scientific studies, including one from the Paris-based French Food Protection Agency conducted in 2000 but not published until the flap arose, is helping clear the name of pesticides.

"Beekeepers have a problem," concedes Christoph Künast, ecotoxicologist in BASF's agricultural products division, "and the problem was severe in spring 2003." An average of 30% of bee colonies did not survive--a dramatic difference from the 5 to 10% considered normal in Europe. In the U.S., beekeepers typically lose one-quarter of their colonies each year.

And those losses can affect a variety of crops that use bees as pollinators. Other pollinators can be used--for tomato pollination, for example, bumblebees are more efficient. However, only honeybees and their hives yield beeswax and honey, which is a tidy little market. According to the 2003 crop report from the U.S. Department of Agriculture's National Agricultural Statistics Service, released at the end of February, U.S. producer honey stocks were 40.7 million lb at the end of the year, up 3% from the year before.

According to Künast, "Fipronil is highly active under lab conditions. Then, indeed, it is toxic to bees. The big 'but' is that under field conditions, it is used in ways where contact with bees is excluded." Fipronil formulations, he points out, are registered in 70 countries for use under the soil as seed treatment. These formulations treat seed such as corn and sunflowers against wireworm and other pests in the soil.

Survival of European colonies has nothing to do with pesticides, Künast argues. One reason for the decline is changing agricultural patterns. For example, in western France, the field acreage of sunflowers has been reduced by about half, reducing the availability of pollen for bees.

HOWEVER, the main problem is probably the relentless spread of the varroa mite, a parasite that also is a virus transmitter. Varroa destructor was first identified on an Asian bee in 1904. In Asia, bees and varroa coexist. But bees in other regions have no such tolerance.

According to researchers at West Virginia University, Morgantown, hive populations infested with mites will succumb in three or four seasons without treatment. In fact, since verroa was first identified in the U.S. in 1987, the feral bee population in the U.S. has been virtually destroyed by the varroa mite, their research indicates.

Bayer, which dubs itself the biggest company in the world to carry out research into varroa control, has several products for this market. The coumaphos Perizin has been on the market for 20 years. One of the company's newer coumaphos formulations, named CheckMite, has been available in the U.S. and Canada under a special registration scheme since 1999, and the company is registering it in Europe and other regions. Other products feature the active ingredient flumethrin.

Pesticide producers are also investigating the use of naturally occurring acids such as formic, lactic, and oxalic acids, as well as natural oils such as neem oil. And some work has been done by West Virginia University into essential oils, including wintergreen, patchouli, spearmint, and tea tree oils.


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