URBANA, Ill. – The Illinois Department of Agriculture receives about 120 pesticide complaints each year; 60% of the complaints stem from a pesticide that moves from its intended target to surrounding land or water. 

Off-target pesticide movement occurs when a pesticide moves out of the area it was sprayed, causing damage to desirable vegetation, humans, and wildlife. Pesticides may move off-target by water or air and become environmental contaminants that can harm waterways, ecosystems, and nearby wildlife. Herbicides, which are weed-killing pesticides, can be especially damaging to plants. 

University of Illinois Extension specialist Michelle Wiesbrook explains that understanding different types of off-target movement, factors that influence each, and prevention is more important than ever before.

“As humans, errors happen, but we need to learn better ways of keeping applications on target with new technology to prevent damage to the environment,” said Wiesbrook.

There are different types of drift. Particle drift is the movement of spray particles. Vapor drift is the movement of spray vapors or gasses. Weather inversions can contribute to pesticide movement when particles hang in the air like fog and move as the wind picks up.

To address off-target issues, Illinois Extension and the Illinois Department of Agriculture train applicators and provide online educational programs and articles. Applicators are required to test every three years.

Historically, Wiesbrook says the prevention of off-target movement is improving.

“Every day during the growing season, there are thousands of acres sprayed in the state, with most of those applications applied according to label directions," Wiesbrook says. "Sometimes, the weather conditions are not in our favor and cause drift. We can't control the weather, but we can control equipment and when we apply. The key is planning well.”

Scouting the land to see if herbicides are needed, reading and following the directions on the herbicide label, and being familiar with the environmental conditions onsite are all strategies for reducing error. 

Wiesbrook's most recent article is found in the Illinois Pesticide Review.

SOURCEMichelle Wiesbrook, Weed Science Specialist, University of Illinois Extension
WRITER: Erin Wunderlich, Writer, University of Illinois Extension

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