Public Notice: Submit Comments by March 2 for Linex® 4L Use on Potatoes

MADISON – The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) is accepting comments through March 2, 2026 for a proposed special pesticide registration to control weeds in potatoes. The special registration proposed by DATCP is for Linex^® 4L herbicide, which is manufactured by Tessenderlo Kerley, Inc. and contains the active ingredient linuron.

Linex^® 4L is currently registered for use in potatoes and other crops in Wisconsin, but not in sandy soils, which is why a special registration is necessary. The special registration would allow potato growers to control broadleaf weeds, especially common ragweed and Eastern black nightshade. These weeds have become a problem in Wisconsin potato production in recent years, particularly in the Central Sands area, where pesticide options are limited. Nightshade also produces poisonous berries that present a hazard in harvesting a food crop.

The special registration would also impose restrictions on where Linex^® 4L may be applied when the depth to groundwater is less than 30 feet, depending on the amount of organic matter in the soil.

This is the third special registration of Linex^® 4L, with a proposed registration expiration of December 31, 2030. No reports of adverse effects were received during the previous registration.

The preliminary environmental assessment indicates that the proposed registration will not require a full environmental assessment. Comments received on or before 4:30 p.m. on March 2, 2026 will become part of the preliminary environmental assessment record. Copies of the assessment can be requested, and comments may be submitted by mail to Otto Oemig, DATCP, PO Box 8911, Madison, WI, 53708-8911; or by email to otto.oemig@wisconsin.gov.

More Information

The special registration process allows states to register additional uses of pesticide products other than those listed on their labels, without prior federal approval. It helps growers address local pest problems that cannot be adequately controlled by any available federally registered product. These problems include insect outbreaks, fungal diseases, and grasses and weeds that outcompete crops. For more information visit https://datcp.wi.gov/Pages/Programs_Services/SpecialPesticideRegistrations.aspx.