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Minnesota Crop News > 2001-2008 Archives

July 7, 2008

Residue of Fungicide Causes Concern in South-central Kansas

Justin McMechan, UM Student Intern
Charla Hollingsworth, Extension Plant Pathologist

Kansas Department of Health and Environment (KDHE) issued restrictions on the movement of grain from several wheat fields in Kansas with concerns about fungicide residues.

Kansas Department of Agriculture (KDA) learned that during the last week of May and first week of June, two or three aerial applicators applied Quilt for an estimated 30 growers on approximately 4200 acres. A combination of a large number of acres and wet weather led to the late applications. The KDA is checking additional aerial applicators' records for late applications to determine how widespread the problem is.

Quilt, a Syngenta product, is used to control a wide variety of cereal leaf diseases. The fungicide requires a 45-day waiting period between application and harvest. KDHE has the authority under state and federal law to prevent grain from entering the food supply if they suspect grain to be unsafe.

Kansas farmer, Leon Sowers had 250 acres embargoed. He said he had an aerial applicator apply Quilt on May 14th for leaf rust. "At the time, none of us were aware there was a 45-day waiting period," said Sowers.

Restrictions were also placed on three elevators that had accepted the grain in order to prevent the movement and mixing of questionable wheat until it had been tested.

"This is entirely precautionary to protect the integrity of Kansas wheat," said Secretary of Agriculture Adrian Polansky.

The restrictions were lifted the following day when test results confirmed that there were no detectible traces of Quilt found. Quilt may have a relatively low toxicity to humans but active ingredient residues of a pesticide must not exceed limits set by the U.S Food and Drug Administration (FDA).

One field in Kansas later tested 0.099 parts per million (ppm) for azoxystrobin one of the active ingredients in Quilt, levels up to 0.10 ppm are allowed. The KDA says that they will be retesting the field to ensure it is within acceptable levels.

It is still unclear what will be done with the wheat if residues are elevated. The FDA says that they will work with the Environmental Protection Agency (EPA) to provide a health risk assessment. The EPA's Hazard Evaluation Division believes that is highly unlikely that any human health thresholds will be exceeded.

In response, the EPA announced that spot grain tests in Nebraska and Kentucky should occur. The Nebraska Department of Agriculture (NDA) has issued inspections of the records from aerial applicators in the southern Nebraska.

"We are continuing to gather information relative to the use of the fungicide in Nebraska," said NDA Bureau of Plant Industry Administrator Rich Reiman. "As with any chemical used in the state, we want to make sure that Nebraska applicators and producers are following all of the label directions. If you are not following the label instructions, you are in violation of the law."

Jim Gray of the North Dakota Department of Agriculture (NDDA) issued a press release on June 27th about the importance of following the label. He stated that the NDDA has not documented any misuse of Quilt or other cereal fungicide in North Dakota.

"Farmers and other pesticide users must understand both when they can apply a specific pesticide to a crop and when they must stop applying the pesticide - that's the pre-harvest interval," said Agriculture Commissioner Roger Johnson of Bismarck, ND. "While misuse of Quilt is likely not an issue in North Dakota, the Kansas incident is a good reminder why it is so important to always read and follow the pesticide label."

As producers and applicators in a society of health conscious consumers, it is important that this matter be taken seriously. The repercussions of misuse will result in more regulations, higher restrictions, and a decline in the reputation of safe, high quality wheat in the U. S.

The following table provides a guideline on the pre-harvest intervals for the last crop growth stage application of fungicides on wheat:

Fungicide Label Pre-harvest Interval
(# of days)
Last Application Stage
Bumper Propimax Tilt 40 up to flag leaf
Caramba 30 up to early flowering
Folicur Orius 30 up to early flowering
Headline —* up to full head emergence
Quadris 45 up to head emergence
Quilt 45 up to flag leaf
Stratego 35 up to flag leaf
*No pre-harvest interval listed for grain.

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