No Carzol SP® for onion thrips in 2009

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Last week, the board of the Michigan Onion Committee asked me to participate in a conference call set up by the EPA to inform us of their intentions regarding a renewal of a Section 18 emergency registration for Carzol SP® (Gowan®) insecticide for onion thrips control in Michigan and throughout the nation. Such a registration was authorized last year, but expired September 15, 2008. It will not be issued in 2009.

According to EPA officials, recently accumulated data indicates that, despite the clear need for an effective tool to control onion thrips, the toxicological risks associated with Carzol make it unacceptable for agricultural use. This is, of course disappointing news for onion growers across the nation. The EPA staff indicated that they understand the importance of thrips control in onions, and that currently registered insecticides are usually not very effective. They are willing to evaluate any other promising materials brought to their attention.

The EPA is concerned about the risks from Carzol SP® and the total exposure from the entire group of carbamate insecticides (ie furadan, sevin). Food residues are one area of concern. An even greater worry, however, is the risk of drinking water contamination from the carbamates. N-methylcarbamate insecticides act by blocking the action of the enzyme cholinesterase, which regulates the flow of nerve impulses.

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