Weeds & Invasive Plants

All Weeds & Invasive Plants Content

Testing Center on the South Dakota State University campus.

SDSU Extension Pesticide Applicator Testing Locations

Whether you are interested in becoming certified as a private or commercial pesticide applicator, SDSU Extension is proud to offer in-person pesticide applicator testing locations throughout South Dakota.

Sunflowers blooming in a South Dakota Field.

Sunflower Production: Late-Season Weed Escapes Should Guide Future Weed Management Plans

Many sunflower fields across the state are far enough along in their development that the window for preventing weeds with residual herbicides has passed. Weed escapes that remain in the field through the remainder of the growing season can contribute seed back to the soil seedbank.

Green soybeans plants with a light grey background. All soybean plants have purple flowers which indicates the plants have reached reproductive stage 1.

Soybean Plants Are Entering the Reproductive Stage (R1): Last chance to spray select herbicides

The summer solstice roughly marks the date when soybean plants switch from vegetative growth to reproductive growth. An important aspect of the reproductive growth stage is that many herbicides can no longer be applied after plants reach any bloom stage.

Redcedar trees in a pasture
Aug 27

Woody Encroachment Field Tour @ Yankton

SDSU Extension and its partners will host a field tour near Yankton on August 27 at 5:30 p.m to discuss woody encroachment treatment options.

Redcedar trees in a pasture
Aug 12

Woody Encroachment Field Tour @ Mitchell

SDSU Extension and its partners will host a field tour near Mitchell on August 12 at 5:30 p.m to discuss woody encroachment treatment options.

: Two photos with various plants that are brown, yellow, and/or green. A blue pen is in the foreground of each photo for size reference.

Clock tells the time of the day, not when the job is done. Is that true for weed management?

Common banter at the farm gate implies farmers work long days to get the job finished. However, weed management may improve if spraying stops at a particular time of day.

A red, weed hoe next to a freshly cut, green weed surrounded by brown soil.

Reminder: Cutoff for over-the-top dicamba products labeled for soybean is June 30 or R1 growth stage in South Dakota

Over-the-top dicamba products for application in soybean have been relabeled for the 2026 growing season. A stipulation for applying these herbicides is a cutoff date of June 30 or R1 soybean.

Cleaned, emptied pesticide containers on a concrete workshop floor.

South Dakota Pesticide Container Recycling

The South Dakota Department of Agriculture and Natural Resources is again offering pesticide container recycling services across the state. View a complete list of 2026 dates and locations.

Wind carrying a cloud of topsoil over a dry, bare field.

2026 Growing Season: Forecasted dry weather and the implications on postemergence herbicide activity

Weather cannot be controlled, but there are variables we can control to help increase the effectiveness of postemergence herbicides during drought conditions.

Red fescue, a red colored grass, in a meadow in the Black Hills National Forest.

Red Fescue (Festuca rubra), A New Grass in the Black Hills: Friend or Foe?

Red fescue (Festuca rubra), a cool-season, dominate rhizomatous grass, has started showing up on disturbed ground near meadows and forests. While it is not a state noxious weed yet, its spread has raised questions from producers.