Scott, Finney and Wichita county Extension offices will conduct their annual Tractor Safety Course in Scott City at the high school vo ag shop from 8 a.m. to 5 p.m. Saturday.

To sign up for tractor safety you must be 14 or 15 years old (or turning 14 this summer).

Cost will be $10. You will need to provide yourself with a sack lunch that day. To sign up for tractor safety please call the Finney County Extension Office at 272-3670, Scott County Extension at (620) 872-2930 or Wichita County at (620) 375-2724.

Marestail control in soybeans

Controlling marestail in soybeans has been a big challenge for Kansas no-till producers. Because soybeans are generally planted later in the season, and marestail generally germinates in the fall or early spring, application timing and weed size are critical factors to successful control.

In the early spring, using a growth regulator herbicide like 2,4-D or dicamba is an inexpensive and effective option to control rosette marestail. In addition, using a herbicide with residual control of marestail helps with weeds that germinate between the fall and early spring burndown and soybean planting. Products that include Canopy EX, Classic, FirstRate, Sharpen or Valor can help provide residual control against several broadleaf species including marestail. Consult the herbicide labels for the required preplant intervals prior to planting soybeans.

As soybean planting nears, marestail control can become difficult because plants will have bolted and be considerably larger. Herbicides to apply as a burndown prior to planting include tank mixes of glyphosate with FirstRate, Classic, Sharpen, Optill or 2,4-D. Be very careful to follow label directions when using 2,4-D prior to soybean planting because the plant-back restriction with these herbicides ahead of soybean can be from seven to 30 days. Sharpen is a relatively new herbicide that has provided good marestail control and can be applied any time before soybean emergence. Maximize marestail control by applying Sharpen in combination with methylated seed oil and at spray volumes of 15 gallons per acre or more.

One additional herbicide to consider as a rescue burndown application to control bolting marestail prior to soybean planting is Liberty. Although, it would be better to control marestail at an earlier stage of growth, Liberty has been one of the most effective herbicides to control bolting marestail. Liberty also has broad spectrum non-selective activity on other broadleaf and grass species if treated at a young growth stage. Liberty is primarily a contact herbicide, so a spray volume of 15 gpa or greater generally provides the most consistent weed control. Liberty tends to work best under higher humidity and warm sunny conditions at application.

Controlling marestail in the growing soybean crop can be the biggest challenge for producers. Glyphosate alone is often not effective on larger or glyphosate-resistant marestail. The most successful treatments for large marestail in Roundup Ready soybeans have been with combinations of glyphosate + FirstRate, glyphosate + Classic or glyphosate + Synchrony.

Another option to control marestail in soybean is to plant Liberty Link soybeans and use Liberty herbicide. It is important to remember that Liberty can only be applied postemergence on Liberty Link soybeans.

This information is provided by Kansas State Extension agronomists Dallas Peterson, weed management specialist (dpeterso@ksu.edu), and Doug Shoup, southeast area crops and soils specialist (dshoup@ksu.edu).