Diatomaceous earth, correctly described in the PR statement below,
is  -  as has already been pointed out  -  certainly not the same thing as
the mineral bentonite.
        Whether either will prove useful to beeks in one or another way is
another question.

R




Natural Product Helps Insects "Bite the Dust"

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ARS News Service
Agricultural Research Service, USDA
Linda McGraw, (309) 681-6530, [log in to unmask]
December 22, 1999
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Remnants from one of the oldest things on earth--diatomaceous earth
(DE)--can help solve one of today's most pressing problems: finding safe
alternatives to insecticides to control insects in homes and food
processing facilities, according to Agricultural Research Service scientists.

DE is dust made from the fossilized skeletons of microscopic aquatic
plants.
ARS researchers are testing new commercial DE products in laboratory
studies. DE is non-toxic to humans, but it kills red flour beetles and
confused flour beetles, two of the food processing industry's worst
insect pests. DE disrupts the insects' exoskeleton or skin, causing the insects
to die from rapid water loss.

According to ARS entomologist Frank H. Arthur, DE could be an
alternative to methyl bromide, an ozone-depleting fumigant scheduled to be
phased out by 2005.

Fluctuations in temperature and relative humidity can affect the
performance of DE products used to control insects. Adult insects were
exposed to DE
at various temperatures (70, 80, and 90 degrees F) and relative humidities
(40, 57, and 75 percent). Exposure to DE at 80 degrees F. and 57 percent
relative humidity for two days killed all red flour beetles, but three days
were required to kill 100 percent of the confused flour beetles. DE kills
insects quicker at higher temperatures and at lower humidities.

Arthur is based at ARS' Grain Marketing and Production Research Center
in Manhattan, Kan. His research also focuses on alternatives to
insecticides used in raw grain storage. While DE is a good alternative to
chemical
insecticides, Arthur stresses the importance of combining a product like
this with good sanitation.

ARS is the chief research agency for the USDA.

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Scientific contact: Frank H. Arthur, ARS Grain Marketing and Production
Research Center, Manhattan, Kan., phone (785) 776-2783, fax (785)
776-2792,
[log in to unmask]
----------

-
Robt Mann
consultant ecologist
P O Box 28878   Remuera, Auckland 1005, New Zealand
                (9) 524 2949