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We've written about the environmental drawbacks of major increases in corn production in the U.S., particularly related to nitrogen runoff into waterways. But another potential problem is looming. Biotech company Monsanto (manufacturer of Bt corn) reported in January that in an effort to cash in on high corn prices, fewer farmers are planting biotech crop refuges designed to control pests. One important outcome could be the dimished effectiveness of a valuable pest control tool for organic and sustainable farmers.

Currently, farmers who plant genetically engineered Bt (bacillus thuringiensis) corn and cotton are required to set aside part of their land to protect against pest resistance. The target is the corn borer and corn rootworm. Engineered Bt corn has the pesticide inserted into the cells of the plant. The pest dies after eating the Bt corn. From a pest control standpoint, the concern is that if too many pests eat too much Bt corn, over time they will develop a resistance to Bt, and the technology will lose its effectiveness. In order to protect Bt corn, the Environmental Protection Agency (EPA) requires farmers to plant at least 20 percent of their corn acres with non-Bt seed to delay insect resistance to Bt traits. The idea is that any pests who are starting to develop a resistance to Bt will mate with others living in the refuge - and thus dilute the development of resistance.

But here's where the credibility of the set aside program breaks down. The EPA doesn't monitor its implementation. It's up to the biotech companies who do the monitoring by calling farmers on the phone and reporting back on compliance. It's hard to see how the industry is a disinterested party in documenting compliance. So when Monsanto reports a potential problem - it's worth paying attention.

In January, Monsanto's Scott Baucum told attendees at the Illinois Crop Protection Technology Conference at the University of Illinois that compliance with the crop set aside system declined in 2007. While Baucum wouldn't say how much compliance had declined, 2006 overall compliance ranged from 80 to 95 percent.

Monsanto and the National Corn Growers Association are so concerned about non-compliance that they have kicked off a new education campaign with postcards to their members and billboards in top corn producing states about the need for farmers to plant Bt refuges, according to DTN (sub required).

The development of pest resistance to Bt could be significant for organic and sustainable farmers. In its natural form, Bt is derived from a soil bacterium that naturally repels plant pests and has been used as a last line of defense by organic or low-chemical farmers in a spray form for decades. Since the natural Bt spray degrades in sunlight and evaporates from plant surfaces within a short period of time, farmers don't have to worry about Bt residues contaminating food or building up in the soil.

After decades of low-priced corn, often below the cost of production, there is enormous pressure on farmers to take advantage of rising corn prices. The potential for increased pest resistance is yet another reason why we need the federal Farm Bill and state policies to help us shift toward more diversified and resilient cropping systems. The biofuel boom has certainly played a role in the massive growth in corn acres and higher prices. But it has also accelerated the need to build a biofuel system based on perennial energy crops.

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