Monarchs, roundup & other pesticides

[Paul Cherubini]

Dave Clermont wrote:

> it [Roundup herbicide] doesn't seem to kill
> the milkweed, leaves become yellow & weird & twisted
> growth appears but it doesn't die.

My experience has also been that Roundup doesn't
necessarily kill off all the milkweed growing in corn and
soybean fields.  Example: I have been monitoring milkweed
abundance in a field at Morris, Minnesota for the past
4 years.   Here's what I've found to date:

In 2002 there was milkweed growing up to 10-15 feet
inside the margins of a field of Roundup Ready soybeans
http://www.saber.net/~monarch/morris2002.jpg

In 2003 the farmer grew corn instead in this same field and
milkweed still grew up to 10-15 feet
inside the margins of the field:
http://www.saber.net/~monarch/morris2003.jpg

In 2004 the farmer switched back to soybeans
and milkweed still grew up to 10-15 feet
inside the margins of the field
http://www.saber.net/~monarch/morris2004.jpg

In 2005 the farmer grew Roundup Ready corn and
there was still some milkweed growing inside the margins
of the field although not quite as much as I had seen in earlier
years:
http://www.saber.net/~monarch/morris2005.jpg

Paul Cherubini
El Dorado, Calif.

 
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