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Avoiding herbicide drift

Spray drift
Figure 1: Spray drift during herbicide application.

As crops and weeds enter rapid growth stages, unfavorable weather conditions can make timely herbicide applications challenging.

To limit yield loss from weed competition, target postemergence herbicide applications before corn and soybean reach the four-leaf and V4 growth stages, respectively. This helps ensure applications are made before weeds exceed 3 to 4 inches, the maximum height for the most effective control on many herbicide labels.

However, when growers rush to complete weed control operations under very windy conditions, herbicide drift and injury to non-target crops can be anticipated. It’s particularly important to pay attention to the risk of crop injury from pesticide drift when fields of Roundup Ready crops are adjacent to non-Roundup Ready crops.

Legal implications: Pesticide drift in Minnesota

Pesticide drift from the site of application into non-target areas violates Minnesota law governing the legal application of pesticides.

While there’s no state law dictating restrictions at specific wind speeds, pesticide users must follow all product label directions and precautions, which may list specific wind speed restrictions.

Requirements can include, but aren’t limited to:

  • Always read and follow all product directions and precautions appearing on (or included with) pesticide containers. Some labels have detailed drift minimization requirements for product use. Others may only have a broad, short statement without details requiring that the applicator prevent drift or not spray “when conditions may result in drift.”

  • Read and follow local, state and federal regulations regarding pesticide application procedures.

  • Know the exact location of the area to be treated, as well as the potential hazard of spray drift or subsequent pesticide movement to surrounding areas.

  • Avoid spray drift. It’s illegal to allow spray drift to move off the target site.

Strategies for avoiding herbicide drift

Making pesticide applications is a substantial responsibility with many consequences if done incorrectly.

Read pesticide labels, check application equipment, be aware of environmental conditions to reduce drift and make the best use of each product. The bottom line: Plan ahead when applying pesticides and consider buffer zones.


How to handle pesticide drift and exposure

Human pesticide exposure

Handling human pesticide exposure takes priority over handling pesticide drift.

Follow the label for first aid and call the Poison Center at 800-222-1222. For medical emergencies, immediately call 911.

Pesticide drift

To report pesticide drift in Minnesota, call the Minnesota Duty Officer at 800-422-0798, day or night, seven days a week. You can also call the Minnesota Department of Agriculture (MDA) Complaint Line at 651-201-6333, Monday to Friday from 8 a.m. to 4 p.m, or file a complaint online.

Report drift complaints as soon as possible, as delays may prevent the Minnesota Department of Agriculture from documenting violations.


David Nicolai, Extension educator; Lizabeth Stahl, Extension educator and Dean Herzfeld, Extension pesticide safety coordinator

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