Does anyone remember when John Obryckil asked why so many fields were planted to Bt corn when they probably do not need the protection? "I have seen where only a very small percent of the corn needs this protection from the insect," Obryckil said last summer. "Why have the poison in the pollen where you don't need it?"

The researcher was not popular last summer. The Iowa State University entomologist had released more research that raised questions about Bt  corn and its threat to butterflies. Now, months later, others are asking Obrycikil's question as planters start rolling in the Corn Belt.

"None of the currently available insect-resistant or herbicide-tolerant corn or soybean varieties is critical for the success of Indiana farmers," says Bob Nielsen, Purdue Cooperative Extension Service corn specialist, echoing comments coming from Extension in  Iowa, Kentucky and Illinois.

"Because these transgenic crop traits are not critical for Indiana  farmers, the choice of whether to grow them or not depends primarily on the  farmer's assessment of the uncertainty of market acceptance for such products  and/or the available seed supply of alternative non-transgenic varieties," says Nielsen.

Because corn borer infestations are historically infrequent across  Indiana, transgenic hybrids offer little economic advantage to most farmers,  Nielsen says. Bt varieties were most effective in controlling corn borer if  planted very early or late in the season, he says. (StarLink corn is not being  sold.)

"Unfortunately, seed companies cannot guarantee zero presence of Cry9C in any seed lot," Nielsen says. "The currently available quantitative tests, when used with appropriate sampling intensities, are capable of detecting the presence of the Cry9C protein at the minimum detectable level of no less than about 0.2 percent, with a 99% probability."

You can find more information at http://www.kingcorn.org/news/articles.01/GMO_Issues-0312.html
or http://www.agry.purdue.edu/ext/corn/cafe/index.html.