You are correct in that the work is not published at this point, although we have submitted preliminary analysis of the survey to be published as a rapid report. I have attached an abstract of a paper to be presented at the Weed Science Society of America. Since we are weed scientists we didn't study the monarchs directly. However, it is well documented that larval stages of this insect are present during corn pollination. An entomologist went to several of the infested corn fields we identified and confirmed that milkweeds in these fields were being used by monarchs. He is also working on getting his results published.

I get very irritated at the way the monarch paper has been attacked and belittled, although anyone who knows anything about Bt and Bt corn will tell you that there is no question that Bt pollen is toxic to monarchs and other lepidopterans (assuming the corn uses an event that expresses the toxin in the pollen). A predominant attitude of many pro-GMO persons has been that windshields will kill more monarchs than Bt pollen, and thus there is no reason to worry about such a 'frivolous' topic. Although there probably are greater threats to the survival of monarchs than Bt corn, I also believe that Bt corn was pushed through the system before the risks to non-target organisms were fully understood (there are a lot of other susceptible insects out there). This is especially true for Iowa and surrounding states where 1/3 of the total land mass is planted to corn. Since less than 5% of the corn acres in Iowa were treated for European corn borer (the target of the Bt), it is incorrect to say that Bt corn has replaced chemical applications that would be more disruptive to insect populations.

In summary, I agree that it is unfortunate that the 'radicals' have singled out this subject as the 'poster child' in their fight against GMO's. However, scientists do themselves no favors by belittling the issue, often with unsubstantiated facts. I believe the original Nature article did raise some issues that were largely ignored in the rush to get these products to the market and show some returns on the investment.

Prof. Dr. Bob Hartzler
Iowa State University Extension Weed Specialist
2104 Agronomy Hall
USA 50011 AMES, U.S.A.

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