Idaho Wheat Commission

News

Weed Management Systems: Italian Ryegrass

Joan Campbell, University of Idaho

An initial Italian ryegrass survey was completed in 2006 and 2007 with 75 Italian ryegrass samples collected from Lewis, Latah, Nez Perce, and Benewah counties in Idaho and Whitman, Spokane, and Walla Walla counties in Washington. Italian ryegrass seed was collected again in 2017 to 2019 from the same areas and an additional 31 sites. Seeds from each sample along with a known susceptible biotype are screened in the greenhouse against herbicides used to control Italian ryegrass. Untreated plants are included from each sample. Screening has been ongoing and will be completed in May.

Post emergence herbicides tested in the second survey include glyphosate, Axial XL, clethodim, Poast, Assure II, Osprey, and PowerFlex HL. No Italian ryegrass samples were resistant to glyphosate. Diclofop is no longer used as Italian ryegrass had a high degree of resistance to this group 1 herbicide. Other group 1 herbicides increased from below 50% in the first survey to 58 to 75% resistance. Clethodim is the exception with resistance levels still below 25%. Screening of pre-emergence herbicides resulted in no sample resistant to Zidua or Outlook. Amber resistance is widespread at 86%. Axiom and Dual Magnum resistance is 25% and 14%, respectively.

Close attention to using herbicide resistant tactics will help keep herbicides effective for managing Italian ryegrass.

June 3, 2026

Idaho’s U.S. Senator Frank Church Wrote BPA’s Rulebook. It Demands Reliable Power, Too.

An opinion editorial written by Will Hart, executive director of the Idaho Consumer-Owned Utilities Association, and Kurt Miller, executive director of the Northwest Public Power Association.

April 7, 2026

Changing diets and demographics creating new opportunities for U.S. wheat

Rising incomes, growing populations, and rapid industrialization is creating increased demand for wheat foods around the world.

April 7, 2026

Idaho ag economic impact hits records

The economic impact of agriculture in Idaho reached $44.5 billion in sales, 17.2% of the state’s total economic output.

April 7, 2026

What is the Most Important Asset on the Farm?

How much time do you spend making sure your equipment is properly maintained? From combines and drills to pickups and silos, the farm has spent a lot of money and you probably have a “correct” way to take care of the tools you’ve invested in. But what is the most important asset on the farm? Quick answer: you and the people around you. Do you allocate as much time and attention on those assets? Probably not.

April 7, 2026

ALERT: Warm Weather Threatens Wheat with Yield Loss

The warm winter weather throughout the state has experts concerned about increased fungal diseases creeping into fields and causing yield loss. Xianming Chen, USDA stripe rust expert in the PNW, is warning farmers to start checking their fields. Chen is predicting that stripe rust will be more widespread and extreme this year than in the past 15 years. The last particularly bad year for stripe rust was in 2011. Experts from the U.S. Wheat and Barley Scab Initiative are also warning about fusarium head blight and vomitoxin (DON) in winter wheat. USWBSI is reminding farmers that the best time to apply fungicides for FHB and DON management is at Feekes growth stage 10.51, when 50% of the main tillers have reached early anthesis (flowering) and up to seven (7) days following.