COLORADO WHEAT DISEASE NEWSLETTER
April 25, 2022
There is one report of virus-like symptoms in Sedgwick County. A neighboring plot had lots of volunteer wheat that likely contributed, since volunteer wheat can harbor the mite that spreads several viruses (wheat curl mite), as well as the virus itself. These samples have not yet been tested, so we do not know if symptoms are indeed caused by a virus, and if so which one(s). There have been no other reports of diseases at this time (including no other viruses, tan spot, or stripe rust). Wheat fields are pretty spotty due to lack of water. Dr. Esten Mason Tweeted a photo of the status of several wheat plots last week (Figure 1). Stands in Kiowa and Kit Carson counties are in overall good condition, but Prowers county plots are showing drought stress. Stands in Yuma county are in poor condition and may be abandoned.
The Colorado Wheat Entomology Newsletter
Written by Dr. Punya Nachappa and Darren Cockrell, covers insect/mite pests and management tips. The newsletters are published bi-weekly during the growing season and are available here: https://coloradowheat.org/category/news-events/wheat-pest-and-disease-update/
DISEASE WATCH AND MANAGEMENT
There are reports of localized, moderate stripe rust pressure in limited areas of Texas and Oklahoma. Stripe rust disease is dependent upon cool, wet weather, and the dry conditions across Colorado will likely inhibit and/or limit rust diseases.
Soil moisture levels are often correlated with stripe rust incidence and can be used as a predictive tool in determining if stripe rust will emerge. This time of year, we look at the soil moisture levels in the southeast. Not much has changed in soil moisture levels, so I still expect that stripe rust pressure will remain low in Colorado.
Growers are strongly encouraged to regularly scout wheat fields for diseases. Particularly, scout for stripe rust and viruses in the coming weeks.
There have been some reports of mild to moderate brown mite pressure in Colorado.
1. Information about the ‘green bridge’ and risks for viral diseases due to volunteer wheat: https://eupdate.agronomy.ksu.edu/article_new/spring-emerged-volunteer-wheat-should-producers-worry-about-wheat-streak-mosaic-virus-and-the-green-bridge-436-4
2. The North Central Regional Committee on Management of Small Grain Diseases (NCERA-184) Fungicide Efficacy for Control of Wheat Diseases Table: https://crop-protection-network.s3.amazonaws.com/publications/fungicide-efficacy-for-control-of-wheat-diseases-filename-2021-04-21-154024.pdf
3. Wheat variety database with stripe rust resistance ratings from field trials: https://wheat.agsci.colostate.edu/database/
4. ‘Making Better Decisions’ 2021 Colorado Wheat Field Days publication: https://webdoc.agsci.colostate.edu/csucrops/reports/winterwheat/wheatreport_2021_WFD.pdf
Many thanks to all who contributed to this report: Tyler Benninghoven, Dr. Esten Mason, Emily Hudson-Arns, Ron Meyer, and Dr. Todd Ballard.