COLUMBIA, Mo. In 2007, a controversial pesticide was approved by the Food and Drug Administration for use on fruit and vegetable crops, mainly in California and Florida. Farm workers and scientists protested the approval of the pesticide because its active ingredient, methyl iodide, is a known carcinogen. Now, MU researchers are studying the molecular structure of the pesticide to determine if the product could be made more efficient and safer for those living near, and working in, treated fields.
Methyl iodide is the active ingredient used in a pesticide known commercially as Midas. Midas is a mix of methyl iodide and chloropicrin, a rat poison, and is used primarily on the fields that will grow strawberries, tomatoes and bell peppers. In a new study published this month in the Journal of Agricultural and Food Chemistry, MU researchers studied why the manufacturer blended the chemicals to determine if a different chemical combination might be possible.
"We found that the two chemicals, methyl iodide and chloropicrin, are mixed to slow the release of methyl iodide and increase its effectiveness," said Rainer Glaser, professor of chemistry in the MU College of Arts & Science. "However, we believe that a different chemical mix could further slow the release of methyl iodide and allow farmers to use less of the pesticide, which would make the area safer for workers and the public."
Methyl iodide is a fumigant, meaning that it fills an air space with gas, suffocating and poisoning the pests within the airspace. Farm workers dressed in protective suits apply Midas in liquid form to fields 10 to 14 days prior to planting and cover future crop rows with plastic sheeting. During that time period, the pesticide is released in gas form, suffocating pests in the top layer of the soil. However, much of the fumigant is useless as it is lost into the atmosphere upon application and during the release period due to ventilation of the area. Al
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University of Missouri-Columbia