The Easiest Way to Control Roundup Resistant Water Hemp and Palmer Amaranth is to Never Let it Come Up! Be Proactive, rather than Reactive. This Program May Help You Save Money and have Better Soybean Yields. Once you have seen the weeds, you are no longer timely!
Fall Program for 2017 Soybean Planting
After the soil cools in the fall is a good time to apply residual herbicides for control of winter annual weeds, downy brome and volunteer wheat, and marestail. After November 1, apply 1.1 oz Cloak EX with 8 oz of Dicamba and 8 oz of 24D. Add 32 oz of 4# glyphosate as needed to control emerged downy brome or volunteer wheat. The Cloak application should do a good job of controlling the winter annuals and marestail. Do Not Delay This Application! The temperatures after Thanksgiving can be cold enough to stop chemical and water applications.
Springtime of 2017, apply 5 oz Authority Max and 1.5 oz Zidua as early as March 15, but no later than April 15. If the weather works right, this will help keep the soil fairly weed free until right before planting. Option #2 at this point is 4 oz Authority XL with 1.5 oz Zidua, rather than the Authority Max. Authority Max has less Classic than Authority XL, reducing the chance of carryover to the subsequent crop.
Assuming the beans are planted May 15 to May 25, and the fields are still clean, plant the beans. Twenty one days after planting apply 16 oz Fomesafen, 42 oz 4# Glyphosate and 3 pints of Warrant. The weeds will be small and easier to kill, plus the Fomesafen and Warrant will help with residual control. If things work well, this would be the last weed treatment.
If weeds have emerged before planting, we have several options. Verdict gives good burndown results and has residual chemical in it. Paraquat has done a nice job on burndown, as long as we have warm temperatures.
Liberty Link soybeans are another option for 2017. For this program, use the same program as outlined above for the fall and the March/April treatment. Twenty one days after planting, apply 29 oz Liberty/Interline along with Clethodim for contact grass control, and Warrant for residual control.
Dicamba Resistant soybeans are not labeled for dicamba yet. Monsanto thinks they will have a label soon. Monsanto thinks the label will be for pre-plant, pre-emerge and post-emerge applications. This will present some drift challenges to non Dicamba resistant soybeans, but this will give us some good options for weed control.
Some producers are thinking about planting with air seeders or drills to get their row spacing down to 15 inches. If the producer can get a good stand of soybeans, the soybeans would canopy quicker than beans in 30 inch rows and help with weed control.
Tillage is an option that has helped some producers. More tillage and less glyphosate has helped with fewer glyphosate resistant weeds.
Fall Program for 2017 Corn Planting
After the soil cools in the fall, apply 1.5# Atrazine with Dicamba and 24D. This should give good control of winter annuals and marestail. Add glyphosate as needed for downy brome and volunteer wheat control, as needed. Once again, this application should be made as soon as possible after the first of November. The soil will be cool enough to slow the breakdown of chemicals and the temperatures are not too cold to apply water and chemicals.
At corn planting time, use 2 quarts of Trizmet II. Add Dicamba and glyphosate as needed. When the corn is V4 to V6, apply glyphosate and 3 ounces of Status. Fields that have been treated in this manner have had consistent control of grasses and broadleaves. Clean corn fields are much easier to rotate to soybeans in the subsequent crop year.