Interesting ...

[Paul Cherubini]

Hank,  the frog / herbicide study was a lab study and may have no
relevance to field conditions.  We learned this lesson with the
monarch butterfly Bt corn scare which turned out to be nothing.
Here in California's central valley  it is routine to hear hundreds 
of frog "singing" at night in late winter in agricultural areas where
atrazine and Roundup are used heavily.

Now monarch scientists are increasingly saying herbicides like
Roundup pose a "major" or even "catastrophic" threat to the 
monarch. Examples:

http://whyfiles.org/083isotope/4.html

He [O.R. (Chip)Taylor} says a major new threat is the widespread use
of corn and soybeans that are genetically resistant to herbicide
like Roundup. Roundup-resistant crops allow farmers to spray 
Roundup, which kills just about anything green.If the herbicide 
becomes virtually ubiquitous, the side effects could be
enormous. "We are cleaning up U.S. agriculture, the weedy fields, in a way
that they've never been cleaned up before," Taylor says. "Monarchs, birds,
and other animals depend  on weediness" in crop fields. Yet the potential
of herbicide-resistant crops is to eradicate weeds. '

Dr. Lincoln Brower Nov. 22, 2000:
http://news.nationalgeographic.com/news/2000/11/1122_monarchs.html.

All over the United States herbicides are replacing costly
mowing as the primary method of controlling weeds
along roadsides, power line right-of-ways, and
agricultural fields‹areas that together comprise much
of the monarch¹s breeding grounds. "Herbicide use at that level,"
says Brower, "is  catastrophic for monarchs."

But University of Nebraska weed scientists say just the opposite:
http://www.ianr.unl.edu/pubs/weeds/g384.htm

"There are several reasons common milkweed is on the
increase in Nebraska. Less tillage is used in crop production 
today than in the past, creating more favorable conditions for
plant establishment and growth. HERBICIDES [e.g. Roundup] 
ARE WIDELY USED TODAY WHICH OFTEN DO NOT 
HARM COMMON MILKWEED BUT CONTROL MOST 
ANNUAL WEEDS THAT WOULD 
OTHERWISE COMPETE WITH IT Cultivated land in eastern 
Nebraska is in row crops most of the time, which provides 
a favorable environment for common milkweed. Irrigation and 
fertilizer use are practices that enhance common milkweed as 
well as crop growth."

"Under present row crop production methods common milkweed 
is spreading and infestations are becoming more severe. Surveys 
indicate common milkweed has increased markedly in row crops 
during a four-year study in eastern and south central Nebraska 
(Table I). Tillage implements cut and drag root sections of the plant, 
which spreads it. Reduced tillage systems provide favorable 
conditions for the development, growth and spread of this
plant. Use of irrigation water and fertilizer also creates a
favorable environment for common milkweed."

 
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