By Blake Jackson
Effective weed management in winter wheat begins before weeds become established. According to Dr. Travis Legleiter, UK Extension Weed Specialist, using a residual herbicide at the right time can play an important role in controlling Italian ryegrass and other winter annual weeds.
For Kentucky wheat growers, herbicides containing pyroxasulfone are among the strongest residual options when Italian ryegrass is a major concern.
Products such as Anthem Flex, Zidua and Fierce EZ contain the same primary active ingredient, but their application windows differ because of their other ingredients and crop-safety requirements.
Research conducted over several years has generally shown similar ryegrass control among these products, with differences more often linked to weather and field conditions.
A key factor is rainfall after application. Activating rain within roughly 10 days can improve herbicide performance. Under favorable conditions, pyroxasulfone products can provide at least 80% control of Italian ryegrass into the following spring. However, some plants may survive, making a postemergence treatment with Axial Bold necessary.
Fields containing ryegrass resistant to Axial Bold present a particularly difficult management challenge because effective postemergence alternatives are limited.
Application timing also affects management. Anthem Flex can be used preemergence, while Fierce EZ offers a 14-day preplant option. Early postemergence applications are available for all three pyroxasulfone products and may extend residual activity into late winter and early spring.
When applying at this stage, growers can add 2 to 3 ounces of a 75DF metribuzin product to address ryegrass that has already emerged, although wheat injury can occur under cold, wet conditions.
Dr. Travis Legleiter notes that growers should select products and application timings based on field conditions, weed pressure and resistance concerns. Proper seedbed preparation, adequate planting depth and adherence to product labels are essential for minimizing crop injury.
Even fields without Italian ryegrass can benefit from residual herbicides. Products such as Finesse Cereal and Fallow and Valor EZ can help control other winter annual weeds and potentially reduce spring herbicide applications.
Growers using Finesse Cereal and Fallow should plan to plant an STS, SR or BOLT soybean variety after wheat.
Photo Credit: gettyimages-dleonis
Categories: Kentucky, Crops, General