Agronomy and Horticulture Department


Date of this Version



Insect Science, Plant Disease, & Weed Science, University of Nebraska Cooperative Extension, Institute of Agriculture and Natural Resources 87(19) (July 31, 1987)


Copyright 1987 University of Nebraska


In This Issue:

  • Late Season Weed Control in Corn and Sorghum
  • Bindweed Control Where Wheat is to be Planted
  • Reap Dogbane Control in the Pall
  • August Lawn Renovation

Late Season Weed Control in Corn and Sorghum

Late season broad leaf weed control in corn and sorghum is possible with 2,4-D. Such a treatment could make harvesting easier and reduce weed seed production. Treatments should be applied no later than flowering stage of weeds for control of seed production. Both corn and sorghum can suffer yield reductions from 2,4-D applied during the flowering period. As a guideline, 2,4-D use on corn can be resumed after the silk turns brown. The use of 2,4-D on sorghum can be resumed after the grain reaches the early dough stage. Sorghum should not be sprayed with 2,4-D between the beginning of head emergence and the milk stage of the grain. These late 2,4-D treatments will not cause lodging or stalk brittleness in the crop.

Bindweed Control Where Wheat Is To Be Planted

Fall is usually an excellent time to make herbicide applications for field bindweed control. However, healthy new growth on the bindweed is essential for good results. Avoid tillage for at least 30 days prior to treatment. Dry weather in some areas has reduced bindweed growth making it more difficult to control. It would be best to wait for rain and new bindweed growth before treating. This could be too late this fall for land going to wheat. September treatments are usually more effective than August treatments.

Hemp Dogbane Control in the Fall

Hemp dogbane approaches the correct stage for treatment with 2,4-D or a combination of 2,4-D + Banvel in late August and early September. Applications should be made after corn is in the brown silk stage or milo is in the soft dough stage. Hemp dogbane roots should have swollen pink buds. Pod set on soybeans in the adjacent area should be complete. The precautions for soybeans are less important where only 2,4-D is used. Treatments can be made until the dogbane leaves begin to yellow. After the dogbane leaves turn color or a frost occurs, treatment will be of little value. Drought stress will reduce control.

August Lawn Renovation

August is the time to get started with turf renovation. Roundup is a useful herbicide for such projects. Skip one or two mowings so there's good growth on the weeds and grass for herbicide intake and activity. Apply 2 1/2 to 3 oz of Roundup/1000 sq ft using 1 gal or less of water. Delay vertical mowing, slicing, coring, and power raking for 7 days.