Weeds & Invasive Plants

SDSU Extension Weed Evaluation Extension Demonstration Available at South Dakota State Fair

September 01, 2020

The SDSU Extension Weed Evaluation Extension Demonstration project will be available to the public at the South Dakota State Fair September 2-September 7.

Thistle Caterpillars Showing Up on Canada Thistle

This week we received reports of caterpillars feeding on Canada thistle. After taking a look at the caterpillars, we determined that they are thistle caterpillars. However, we typically don’t see thistle caterpillar activity in S.D. until July or August. So why are they showing up so early this year?

Is Herbicide Carryover a Concern in Wet Weather?

Wet conditions have forced the need to change planting plans. In some cases, crops are planted in areas that were not planned for that crop this year. One factor in moving crops that cannot be overlooked is carryover. Does the ground to be planted have a carryover restriction for the desired crop to be planted?

June 2019 Climate Outlook for South Dakota

As South Dakota emerges from the wettest 12-month period in 124 years of climate recordkeeping (June 2018-May 2019), June has started warmer and drier than average. The outlook, however, turns towards cooler and wetter than average again for the middle of the month.

July 2019 Climate Outlook: Challenges Continue

This year’s seasonal pattern of wetter than average conditions is projected to continue through July and the rest of the summer season. The latest climate outlook, released June 20, 2019, shows an increased chance of wetter than average conditions in the next one to three months for the state of South Dakota.

Wet Conditions Likely Into Fall Season

Many locations in South Dakota have already received as much precipitation this year as they do in an entire average year. The latest climate outlook from NOAA’s Climate Prediction Center shows increased chances of wetter than average conditions to continue into the fall season.

August 2019 Climate Outlook: Cool and Wet

According to the latest climate outlook update, odds are favoring that August 2019 will be cooler than average. The update was released by NOAA’s Climate Prediction Center on July 31, 2019.

Glyphosate Resistance in Soybeans

Many weeds have developed glyphosate resistance in the past few years. Many producers who use Roundup Ready soybeans have a temptation to rely on glyphosate products to control post-emergent weeds, causing them to potentially become resistant to the chemical. If producers are unable to gain control over the weed, then weed competition will cause a significant yield loss.

SDSU Research Shows Effects Of Volunteer Corn In Corn And Soybeans

In 2007, researchers at South Dakota State University indicated that volunteer corn is much less competitive in corn than soybean. The South Dakota study (Alms et al. 2007) evaluated the full season effect of a range of volunteer corn densities (800-14,000 plants/acre) on both corn and soybean and reported yield losses that ranged from 0% to 13% in corn and 0% to 54% in soybean.

Spring Dandelion Control In Soybeans

Dandelion has become much more of a problem as farming practices have changed. Less tillage and increased use of glyphosate resistant crops along with reduced use of residual herbicides have allowed some perennial weeds such as dandelion to prevail.