Herbicide Recommendations for Soybeans: Postemergence Grass Herbicides

Pub 75: Guide to Weed Control > Soybeans > Herbicide Recommendations for Soybeans: Postemergence Grass Herbicides

Excerpt from 2008 Chapter 11, Publication 75, Guide to Weed Control, Order this publication

Precautions

Apply to emerged annual grasses and volunteer cereals in 2-leaf to tillering stage and volunteer corn and quackgrass in the 2-6 leaf stage.
Use the 0.38 L/ha (0.15 L/ac) rate of Assure II for control of volunteer corn, volunteer cereals long spined sandbur and green foxtail.
The 0.5 L/ha (0.2 L/ac) rate of Assure II will suppress quackgrass and also control barnyard grass.
Use the 0.75 L/ha (0.3 L/ac) rate of Assure II for control of quackgrass.
Do NOT apply to soybeans within 80 days of harvest.

Precautions

Apply to emerged annual grasses in the 1-6 leaf stage, which are actively growing while crop is small enough to permit thorough coverage.
A second application may be necessary to control later emerging grasses.

**Poast Ultra + Assist or Merge**
Trade Name	Poast Ultra	+ Assist	or + Merge
Active Ingredient	sethoxydim	+ oil concentrate	or + surfactant/solvent
Formulation	450 g/L
Rate per hectare (active)	0.15 to 0.2 kg/ha	2 L/ha	1 L/ha
Rate per hectare (product)	0.32 to 0.47 L/ha	2 L/ha	1 L/ha
Rate per acre (product)	0.13 to 0.19 L/ac	0.8 L/ac	0.4 L/ac

Precautions

Apply the 0.47 L/ha (0.19 L/ac) rate for wild oats or volunteer cereal control.
Apply Poast Ultra to emerged grasses in the 1-6 leaf stage during active growth while crop is small enough to permit thorough spray coverage.
Complete control is normally obtained 7-21 days after application. A second application may be necessary to control grasses that emerge after the first treatment.
Use Merge for conditions or weeds requiring medium to high rates of Poast Ultra.
Water rates of 100-200 L/ha (40-80 L/ac) provide the best results.

Precautions

Apply at 1-3 leaf stage of actively growing quackgrass in 110-200 L/ha (44-80 L/ac) water.
Thorough preplant tillage will result in more uniform quackgrass emergence.
Crop competition and inter-row cultivation 7-14 days after application will assist in quackgrass control for 6-8 weeks.

Precautions

Soybeans are tolerant at any growth stage.
Apply when annual grasses and volunteer cereals are in the 2-6 leaf stage.
Use the higher rate for quackgrass control. Apply to quackgrass in the 2-5 leaf stage.
Add the surfactant Amigo at 5L/1000 L of spray solution to the low herbicide rate and 10L/1000 L of spray solution to the high herbicide rate for quackgrass control.

Precautions

Precautions

Apply at the 2 to 4 leaf stage of annual grasses and the 3 to 5 leaf stage of quackgrass or wirestem muhly. Use the 2 L /ha rate of Venture for wirestem muhly.