Considerations for Weed Management in 2016

Here is the final installment of considerations for weed management in 2016.


Steps for Successful Weed Management in Glufosinate-Resistant (Liberty Link) Soybean


Step 1:

Plant Liberty Link soybean seed into a weed-free seedbed

Achieve a weed-free seedbed through the use of:

                          1) Preplant tillage

                          2) Effective burndown herbicide(s)

                          3) A combination of tillage and burndown herbicides


Step 2:

Select and apply within 14 days of planting a soil-residual herbicide that targets your most problematic weed species.

For waterhemp or Palmer amaranth, select a product containing the active ingredients from one of the following categories of control:

Excellent                                 Good                                                 Acceptable

sulfentrazone                         pyroxasulfone                                   S-metolachlor/metolachlor

flumioxazin                             metribuzin                                         acetochlor

                                              fomesafen+metolachlor                     dimethenamid


*Excellent: greatest efficacy on Amaranthus species and longest residual control

Good: good efficacy on Amaranthus species, residual control generally not as long

Acceptable: stronger on grass species but with some activity on Amaranthus species


Step 3:

Apply Liberty at 32 fluid ounces per acre when waterhemp or Palmer amaranth are less than 4 inches tall. Be sure to apply in a minimum of 15 gallons per acre carrier volume with nozzles that produce a medium droplet. Include AMS (8.5 lb/100 gallons) with all applications. Add lactofen-, fomesafen-, or acifluorfen-containing products for a second site of action against PPO-susceptible Amaranthus species.


Step 4:

Scout treated fields within 7 days after application. If control of waterhemp or Palmer amaranth was not complete, or if another flush has emerged, retreat with 22-29 fl oz plus AMS. Rogue any survivors from the field before the plants begin to flower.




Helpful reminders:

1) Liberty is NOT Roundup. Applying Liberty with the same equipment set-up used for applying Roundup increases the likelihood of performance complaints.

2) Liberty works best with bright sunshine and high humidity. Avoid spraying after 6:00 p.m.

3) Ensure thorough coverage of weeds with carrier volumes between 15–20 gallons per acre. Applications made at higher gallons per acre result in fewer performance complaints.

4) AMS is the most reliable spray additive. Add a minimum of 8.5 lb/100 gallons.