What’s new in cereal-crop, forage-grass weed control
In February’s issue, Penn State University Extension weed specialists Bill Curran and Dwight Lingenfelter teamed up with Cornell University’s Russ Hahn for an update on corn and soybean weed control. They noted that common chickweed seemed to be developing resistance to Harmony SG, Harmony Extra and products containing thifensulfuron’s mode of control in small grains.
• Two products hold promise for chickweed control in wheat.
• Paramount is the only labeled grass controller for grass forages.
• Weed size, additives and spraying conditions affect control.
Following is a Curran-Lingenfelter-Hahn update on new products and labels for small grains and herbicides.
Products not expected to be labeled in 2011 for New York are noted with an asterisk (*).
Weed killers for small grains
Huskie 29.6L* (Bayer) contains pyrasulfotole (an HPPD-inhibitor) plus bromoxynil (Buctril). It controls common chickweed, wild buckwheat, mustards, prickly lettuce, lambsquarters, pigweed, smartweed, ragweed and velvetleaf in wheat, barley and triticale.
Apply it plus an ammonium sulfate solution or a urea-ammonium nitrate solution to small grains up to flag-leaf emergence, and to actively growing weeds with one to four leaves. You can also tank-mix it with other approved pesticides, using liquid nitrogen as a carrier in wheat.
Do not apply Huskie to crops undersown with legumes. Soybeans can be planted 4 months after application; alfalfa, corn, and potatoes after 9 months.
PowerFlex 7.5WDG* (Dow) is a new ALS-inhibitor herbicide containing pyroxsulam. It controls annual ryegrass, downy brome and cheat plus a few annual broadleaves such as non-ALS-resistant chickweed, mustards, henbit, wild buckwheat and hairy vetch.
Fall applications seem to provide the best control of grassy weeds. Apply once wheat reaches the three-leaf stage.
PowerFlex has a favorable crop rotation time frame. Soybeans can be planted after 3 months; other crops can be planted after 9 months.
New for grass forages
Paramount 75WG* (BASF) contains quinclorac as an active ingredient, and can be applied in cool-season grass pastures or hay. It’s currently the only herbicide labeled that controls some annual grasses in grass forages — foxtails, large crabgrass and barnyardgrass. It also has activity on broadleaves such as lambsquarters, ragweed, velvetleaf, annual morningglory, dandelion and field/hedge bindweed.
It can be applied in bromegrass, tall fescue, Kentucky bluegrass, orchardgrass and ryegrass. It’s also labeled for several warm-season grasses.
A seven-day waiting period is required before cutting. Paramount will severely injure or kill clovers, alfalfa and other legumes. Be cautious of crop rotation restrictions.
For more specific product details, rate recommendations and more about weed management, visit weeds.cas.psu.edu.
This article published in the March, 2011 edition of AMERICAN AGRICULTURIST.