Weeds

A potential scenario encountered each growing season is corn planted in fields where no soil-residual herbicide was applied. If the corn has not yet emerged, the soil-residual herbicide can be applied as originally planned. But, what if the corn has emerged and the soil-residual herbicide has not been applied? Can the application proceed as planned, or will a different product need to be selected? The answer depends on the respective herbicide.
Most, but not all, soil residual herbicides can be applied after corn has emerged.…

The weed science program at the University of Illinois invites all weed management practitioners to our annual weed science field tour on Wednesday, June 28 at the Department of Crop Sciences field research location known as the Clem Farm, located at 1114 County Road 1200 East, Champaign. Registration begins at 7:30 a.m. and the tour will start at 9:00 a.m. Preregistration is not required, but please let us know in advance if you will be bringing a large group of participants so we can plan accordingly for meals.…

Pest management practitioners will increasingly find changes to many pesticide labels as the United States Environmental Protection Agency (EPA) begins to implement requirements mandated by the Endangered Species Act (ESA). We encourage all who are involved in pest management disciplines (farmers, applicators, scientists, etc.) to become more familiar with the ESA and how the EPA proposes to meet the agency’s requirements under ESA when registering or reregistering pesticides.
Dr. Lee Van Wychen is the Executive Director of Science Policy for the Weed Science Society of America (WSSA).…

The United States Environmental Protection Agency (US EPA) issued new state-specific application restrictions for dicamba-containing products labeled for use in Illinois dicamba-resistant soybean varieties. The three dicamba products (i.e., XtendiMax, Engenia, Tavium) cannot be applied after June 12 or the V4 soybean growth stage, whichever comes first. We remind applicators these new restrictions are in addition to the existing application restrictions imposed by the Illinois Department of Agriculture that include:

1. A pesticide containing dicamba shall not be applied on soybeans if the air temperature at the field at the time of application is over 85 degrees Fahrenheit or if the National Weather Service’s forecasted high temperature for the nearest available location for the day of application exceeds 85 degrees Fahrenheit.

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Herbicides applied in the fall often can provide improved control of many winter annual weed species compared with similar applications made in the spring. Marestail is one example of a weed species that is often better controlled with herbicides applied in the fall compared with the spring. An increasing frequency of marestail populations in Illinois are resistant to glyphosate, and resistance to ALS-inhibiting herbicides also is present in Illinois populations. Targeting emerged marestail with higher application rates of products such as 2,4-D in the fall almost always results in better control at planting compared with targeting overwintered and often larger plants with lower rates of 2,4-D in the spring.…

Wheat harvest marks the end of one cropping cycle and the beginning of a second. In parts of central and southern Illinois, farmers frequently opt to plant double-crop soybean following wheat harvest, with hopes that the first “killing” frost will be late enough to allow the soybean to reach maturity. Wheat stubble fields not planted with a second crop often become populated with a “crop” of summer annual (and sometimes perennial) weed species. Unlike double-crop soybean,…

A potential scenario of planting delays will be corn planted in fields where no soil-residual herbicide was applied. If the corn has not yet emerged, the soil-residual herbicide can be applied as originally planned. But, what if the corn has emerged and the soil-residual herbicide has not been applied? Can the application proceed as planned, or will a different product need to be selected? The answer depends on the respective herbicide.
Most, but not all, soil residual herbicides can be applied after corn has emerged.…