This was posted to Dplex-L email list today. For those of you not subscribed, I have posted it here for you to read.
From: Chip Taylor <email@example.com>
Date: Fri, Oct 8, 2010 at 12:22 AM
Lots of things we do as a society have unintended and totally unexpected consequences. As most of you know, the adoption of Roundup Ready soybeans and corn has resulted in a significant loss of monarch habitat - as I have pointed out in postings to the Monarch Watch Blog and earlier, the monthly updates. There are about 150 million acres planted in corn and soybeans each year and the adoption rate of Roundup Ready soybeans, which are used in rotation with corn, is estimated to be at least 90%. My interpretation is that we have lost about 100 million acres of monarch habitat due to the adoption of these GMO crop lines. I haven't seen milkweed even as a low level contaminant in corn or soybeans in years nor have several of my colleagues (see ref below). For an extended and perhaps clearer exposition of these points, please see (I'll find these later - it's late).
The report below documents another unintended consequence of the planting of GMO crops such as Bt corn - namely the contamination of waterways with the Bt protein (Cry1Ab) that is intended to kill insects, especially Lepidoptera that attempt to feed on the stems, foliage, roots or ears of the corn. The GM engineered protein, as you will see, has been found in waterways but how did it get there? Is it through direct runoff from fields that have been harvested? Is it from roots that extrude the protein in the process of controlling rootworms? Or, is it from the breakdown of corn tissues that results in the formation of a dust containing the protein that eventually makes its way to the water courses? All three avenues of contamination may be occurring. However, if the Cry1Ab protein is airborne and in sufficient quantities on the surfaces of foliage, it may well be contributing to mortality of Lepidoptera and in some cases beetles well outside the boundaries of the corn fields. Clearly, more work is needed to determine if the escaped Bt protein is a hazard to non-target insects, either in the aquatic habitats or on land.
The following paper in press is relevant to this discussion.
In Press: Reduction in common milkweed (Asclepias syriaca) occurrence in Iowa cropland from 1999 to 2009, Hartzler, R.G., 2010, Crop Protection Articles not published yet, but available online
The role of common milkweed in the lifecycle of the monarch butterfly has increased interest in the presence of this weed in the north central United States. An initial survey conducted in 1999 found that low densities of common milkweed occurred in approximately 50% of Iowa corn and soybean fields. In 2009, common milkweed was present in only 8% of surveyed fields, and the area within infested fields occupied by common milkweed was reduced by approximately 90% compared to 1999. The widespread adoption of glyphosate resistant corn and soybean cultivars and the reliance on post-emergence applications of glyphosate for weed control in crop fields likely has contributed to the decline in common milkweed in agricultural fields. © 2010 Elsevier Ltd. All rights reserved.
From: "Kim Flottum" <Kim@BeeCulture.com>
Subject: CATCH THE BUZZ - GMO Corn Pesticides Found In Stream Water X-Ezezine: 1636.21008.4009)
This ezine is also available online at:
http://home.ezezine.com/1636/1636-2010. ... chive.html
CATCH THE BUZZ
GMO Pesticides Released Into Environment
In a paper published this week in the Proceedings of the National Academy of Sciences, Cary Institute aquatic ecologist Dr. Emma Rosi-Marshall and colleagues report that streams throughout the Midwestern Corn Belt are receiving insecticidal proteins that originate from adjacent genetically modified crops. The protein enters streams through runoff and when corn leaves, stalks, and plant parts are washed into stream channels.
Genetically-modified plants are a mainstay of large-scale agriculture in the American Midwest, where corn is a dominant crop. In 2009, more than 85% of U.S. corn crops were genetically modified to repel pests and/or resist herbicide exposure. Corn engineered to release an insecticide that wards off the European corn borer, commonly referred to as Bt corn, comprised 63% of crops. The tissue of these plants has been modified to express insecticidal proteins, one of which is commonly known as Cry1Ab.
Following an assessment of 217 stream sites in Indiana, the paper's authors found dissolved Cry1Ab proteins from Bt corn present in stream water at nearly a quarter of the sites, including headwater streams. Eighty-six percent of the sampled sites contained corn leaves, husks, stalks, or cobs in their channels; at 13% of these sites corn byproducts contained detectable Cry1Ab proteins. The study was conducted six months after crop harvest, indicating that the insecticidal proteins in crop byproducts can persist in the landscape.
Using these data, U.S. Department of Agriculture land cover data, and GIS modeling, the authors found that all of the stream sites with detectable Cry1Ab insecticidal proteins were located within 500 meters of a corn field. Furthermore, given current agricultural land use patterns, 91% percent of the streams and rivers throughout Iowa, Illinois, and Indiana -some 159,000 miles of waterways-are also located within 500 meters of corn fields.
Rosi-Marshall comments, "Our research adds to the growing body of evidence that corn crop byproducts can be dispersed throughout a stream network, and that the compounds associated with genetically-modified crops, such as insecticidal proteins, can enter nearby water bodies."
After corn crops are harvested, a common agricultural practice is to leave discarded plant material on the fields. This "no-till" form of agriculture minimizes soil erosion, but it also sets the stage for corn byproducts to enter nearby stream channels.
Rosi-Marshall concludes, "The tight linkage between corn fields and streams warrants further research into how corn byproducts, including Cr1Ab insecticidal proteins, potentially impact non-target ecosystems, such as streams and wetlands." These corn byproducts may alter the health of freshwaters. Ultimately, streams that originate in the Corn Belt drain into the Mississippi River and the Great Lakes.