By Blake Jackson
Winter annual weeds such as common chickweed, henbit, marestail, and winter annual grasses can compete with fall-seeded small grains during late fall and early spring.
Heavy weed pressure may slow crop development and reduce yield potential, according to Dwight Lingenfelter, Extension Associate in Weed Science with Penn State Extension.
Harmony Extra and its generic equivalents remain widely used for broadleaf weed control in small grains. Regional trials have generally shown more reliable weed control from fall applications than spring treatments.
However, herbicide performance varies by weed species and resistance patterns, making alternative products and tank mixes important tools.
For common chickweed, Harmony Extra and Quelex continue to provide control in many areas, although resistant populations are emerging. Where ALS-resistant chickweed is present, growers can consider tank-mixing with Starane Ultra or Pixxaro, or incorporating metribuzin products such as Metricor. Fall treatment is often preferred because chickweed can become difficult to manage by spring.
Marestail is more responsive when treated while young. POST applications of products containing 2,4-D or dicamba, as well as Huskie, Quelex, and Stinger, can provide control, particularly when plants are less than 4 inches tall.
Speedwell species can be challenging because several common small-grain herbicides provide limited control. Harmony Extra combined with Quelex or Starane Ultra can improve control of ivyleaf speedwell. Finesse may provide control of certain annual and perennial species, while PowerFlex HL, Aim, or Metricor may suppress smaller plants.
For troublesome grasses, Anthem Flex, Zidua, Osprey products, and PowerFlex are among the more consistent choices for brome species and annual ryegrass. Axiom, Finesse, Metricor, and other labeled products may also provide activity depending on the species.
Roughstalk bluegrass is best treated during fall or early spring while plants are small. Research indicates that Osprey can provide particularly consistent control, while PowerFlex HL, Axial XL/Bold, and other labeled products may also be effective.
Growers should carefully follow application limits and crop-rotation restrictions, particularly when double-cropping soybeans.
Effective weed management also depends on application practices. Lingenfelter recommends following product labels for required adjuvants, spray coverage, and environmental conditions.
Spray volumes of 15 to 20 gallons per acre can help provide uniform coverage. Cool, cloudy conditions, wet foliage, or inactive weed growth can reduce herbicide performance.
Growers planning to frost-seed or drill companion crops such as red clover should also check herbicide recrop restrictions before treatment.
Photo Credit: gettyimages-zoomtravels
Categories: Pennsylvania, Crops