"NLP Wessex", INTERNET:nlpwessex@bigfoot.com
22.05.99 05:59
Another Monarch Study - herbicide resistant GM crops may ALSO damage butterfly
Because of the intense discussion in the media this week about the potentially damaging
effect of Bt "INSECTICIDAL" GM crops on Monarch butterflies in the US we are
reissuing the message below for those who may have missed it in March.
This article - based on a study published in 'Science' earlier this year -
suggests that Monarch butterflies may also be at risk through "HERBICIDE
RESISTANT" GM crops, such as Roundup Ready varieties.
NATURAL LAW PARTY WESSEX
nlpwessex@bigfoot.com
www.btinternet.com/~nlpwessex
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-----Original Message-----
From: NLP Wessex <nlpwessex@bigfoot.com>
Date: 30 March 1999 21:06
Subject: New concerns from US on effects of GM crops on biodiversity
(As the article below reveals even US University agronomists are now
starting to become concerned about
adverse effects of GM crops on biodiversity. This is based on a study
published in 'Science' in January.
>---------------------------------------------------------------------------
Monarch butterflies and herbicide resistant crops
Bob Hartzler
Iowa State University
January 26 - What's the connection between these two organisms you ask?
The monarch migrates each year from southern Canada and the eastern half of the
U.S. to a few small sites in the mountains of central Mexico. Researchers
in Saskatoon, Saskathewan conducted a study to determine the range of
monarchs during their summer stay in the US and Canada. They found that
approximately half of the monarchs were from a relatively narrow-swath from
Nebraska to Ohio.
The researchers were surprised that so much of the population was
concentrated in the heart of the cornbelt. They expressed concern about the
rapid changes in weed control practices occurring in this region. Monarch
larvae feed exclusively on milkweed plants, thus reductions in milkweed
populations could have a dramatic impact on monach reproduction. The use of
herbicide resistant crops (Roundup Ready, Liberty Link, IMI corn) could
provide more effective control of milkweed than traditional herbicides, thus
the concern.
Several factors need to be considered when looking at the impact of HRC's on
monarch butterflies: 1) Will the rates and timing of herbicide applications
made to control annual weeds have a significant impact on milkweed
populations?, 2) What percentage of milkweed in the corn belt is found in
row crop acres vs in roadsides, pastures and other non-row crop areas?, 3)
Do monarchs have a site preference for egg laying (row crop vs non-row crop)?
The researchers pointed out that their findings represent only a single
year's distribution of monarch butterflies and may not represent historical
patterns. However, it does illustrate the potential impact changes in weed
management strategies could have on the ecosystem.
Source: Monarchs and their roots. 1999. Science 283 (Jan 8):171.
Prepared by Author, extension weed management specialist, Department of
Agronomy, Iowa State University
For more information contact:
ISU Extension Agronomy
2104 Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1923
Fax: (515) 294-9985
E-mail: agronomy@exnet.iastate.edu
http://www.weeds.iastate.edu This site designed
and managed by Brent
Pringnitz. Send questions and comments to bpring@iastate.edu
Page last updated on: 02/20/99
Common chemical and trade names are used in this publication. The use of
trade names is for clarity by the reader. Inclusion of a trade name does not
imply endorsement of that particular brand of herbicide and exclusion does
not imply nonapproval.