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Wheat & Small Grains Timely Topics

It’s Time to Scout for Blackleg in Winter Canola

If you haven’t already been walking your canola fields, now is the time, particularly after the very wet fall, warm temperatures right up to snow cover, and the extensive period of snow cover that added up to what can be perfect conditions for blackleg. In winter canola, look for lesions on primarily the lower leaves and leaf material that died back during the winter. The center of the lesions will have tiny black specks (pycnidia). Residue from previous canola crops and cover crops containing Brassica species should also be observed. Collect suspicious leaves, stems, and/or residues, and drop off or mail to WSU, UI, or OSU.

Here is a Blackleg in Canola FAQ document, and here for a blackleg update from WOCS.

Both documents include who to contact at WSU, OSU and UI for assistance.

Picnidia_blackleg P1010135_tn P1010151_tn

What A Difference A Year Makes

Nic Loyd; WSU AgWeatherNet Meteorologist; www.weather.wsu.edu

If you have been wondering when warmer, late spring-like weather will finally arrive, you are probably not alone.  Temperatures in Washington have generally been near or below normal since December.  In fact, the 2016/2017 winter season (December to February) was central Washington’s coldest winter since 1984/1985.  However, it is important to note that the recent chill in early 2017 is only half of the story.  Although the cold 2016/2017 winter and the lack of prolonged springtime warmth so far this year may seem highly unusual, it is not, in a historical sense, as abnormal as one may suspect.  Much of the surprise of the early 2017 climate is related to the extreme warmth of the mid-2010s, as well as the suddenness of the pattern shift toward colder conditions that occurred in December 2016.  The interval from the spring of 2014 until November 2016 was one of unprecedented warmth for central/eastern Washington.  In fact, the temperature anomaly of central Washington’s two-year period from mid-2014 to mid-2016 (+3.9 deg) was almost double that of the now-second warmest (non-overlapping) biennium on record (+2.1 deg; 1990 to 1992).

The 2017 accumulated GDD (Growing Degree Days) total (base temperature 32 degrees F) for Pullman (through April 24) was 747 units, which is somewhat below the 2009-2016 average of 829 units.  However, the 2017 value is well below that of recent years (1081 and 1149 units in 2015 and 2016).  These numbers are illustrative of the fact that the perceived chill of 2017, though somewhat justified, is partly the result of the stark contrast with the remarkable warmth of the previous two years.

January 1 to April 24 Accumulated Growing Degree Days

Base Temperature 32˚F
Location 2017 Recent Avg Difference
Pullman 747 829 -82
Ritzville 710 893 -183
Fairfield 663 763 -100

 

For further GDD information, please see Growing Degree Day Calculator.

Given the volatility of our recent climate, one may reasonably wonder what weather regimes are anticipated for the near future.  Seasonal outlooks for later in 2017 suggest modest but appreciable odds that the state’s temperatures will again become generally warmer than normal.  Long range weather forecast models and decadal trends show an enhanced probability of above normal temperatures this summer, although abnormally cool waters in parts of the nearby Pacific Ocean act to slightly diminish those chances.  There is also a slight tilt toward abnormal dryness, although few clear signals exist regarding potential seasonal precipitation anomalies for the summer of 2017.

El Niño is a critical question mark going forward, and its ultimate strength/presence should significantly influence next winter’s climate pattern.  Unlike the weak La Niña conditions during the chilly 2016/2017 winter season, the notable potential for a weak to moderate El Niño augments the likelihood of a relatively warmer and drier winter of 2017/2018.  However, despite some indicators such as dynamical forecast models pointing strongly in that direction, other tools including historical analogs are more tempered about the eventual evolution of a robust El Niño event.  Therefore, its ultimate development later this year is favored but not yet certain.  Regardless of how Washington’s near-term climate patterns unfold, it seems likely that we can expect additional climatic surprises in the coming months and years.

For additional weather data and decision support information, please visit AgWeatherNet’s website.  To find weekly weather outlooks for Washington State, please select Outlook from the main page of the website, or visit the current outlook page.


For questions or comments, contact Nic Loyd by email at nicholas.loyd@wsu.edu.

 

Stripe Rust Update – April 2017

Dr. Xianming Chen, USDA-ARS Research Plant Pathologist in Pullman, and Dr. Mike Flowers, Oregon State University Extension Cereal Specialist, released disease updates (Dr. Chen’s update and Dr. Flower’s update) during the past week.

Not surprisingly, stripe rust has continued to develop on winter wheat across the region and is relatively easy to find.  Dr. Flowers reported finding stripe rust at variety testing locations near Dufur and Moro, OR, and in a commercial field near Moro. Dr. Chen reported finding actively sporulating stripe rust during the week of April 5 in over 80% of the approximately 70 fields checked in Adams, Benton, Columbia, Franklin, Garfield, Walla Walla, and Whitman Counties in WA, and Umatilla County in OR.

Stripe rust was most active near Walla Walla and Pendleton, where many fields have been sprayed with fungicide already. In other areas, rust ranged from 1 to 5% and is less severe than last year at this time due to lower temperatures. The Palouse in Whitman County is an exception, with stripe rust appearing about one month earlier than normal and similar to the severe epidemic years of 2011 and 2016.

Current weather forecasts continue to favor rust infection and spread, raising the potential for another severe stripe rust epidemic year. High-temperature adult-plant resistance (HTAP) has not kicked in yet and won’t become fully effective until nighttime/daytime temperatures are above 50°F/65°F.  Going forward, it will be important to continue scouting all winter wheat fields and consider using a fungicide with herbicide application if the variety is moderately susceptible or susceptible (rating 4 or greater in the Seed Buyers Guide) or active stripe rust is found on 2-5% of the plants in a field regardless of variety rating. Continue to monitor sprayed fields throughout the spring, especially near the end of fungicide effectiveness (3 to 4 weeks, depending on the fungicide).  For spring wheat, plant the most resistant variety available, preferably those rated 1 to 2.

Additional rust updates will be released as the growing season continues and conditions change. You can find additional information on stripe rust, including photos showing rust percentage, under Foliar Fungal Diseases in the Disease Resources section of the WSU Wheat and Small Grains website.


For questions or comments contact Tim Murray by email (tim.murray@wsu.edu), by phone (509) 335-7515, or Twitter (@WSUWheatDoc). For additional information contact Dr. Chen at xianming@wsu.edu or (509) 335-8086; or Mike Flowers at (541) 737-9940 or at Mike.Flowers@oregonstate.edu.

Proposed Rule Changes for Restricted Use Herbicides

The Washington State Department of Agriculture is considering rule changes affecting the use of restricted use herbicides. The possible rule changes were agreed upon by a workgroup consisting of various agricultural sector representatives and representatives from WSU.  The existing rules covering restricted use pesticides are extensive, complex, and confusing. For example, there are over 50… » More ...

Raising the Quality Bar

Each spring the Idaho, Oregon and Washington grain commissions publish the Preferred Wheat Varieties brochure.  The document ranks current commercial wheat varieties based on their end-use quality and the 2017 edition has just been published! The Preferred Wheat Varieties brochure serves the grain industry by providing customers of Pacific Northwest (PNW) wheat with a ranking… » More ...

Podcast Dissects Falling Number Phenomenon

Learn more about the discount that cost Eastern Washington wheat farmers at least $30 million and perhaps as much as $140 million in 2016. Episodes 12 & 13 of the Washington Grain Commission-sponsored podcast, Wheat All About It! both address falling numbers. The two podcasts are from a falling numbers panel held during Spokane Ag… » More ...

Pink Snow Mold Destruction Discovered in Area Wheat Fields

Furrows of bleached-looking leaves of winter wheat damaged by pink snow mold in a Prescott, Wash., field.
By Linda Weiford, WSU News

Damage caused by snow mold in some eastern Washington wheat fields has surprised a Washington State University plant expert who has studied the fungus for nearly four decades.

Melting snow is exposing patches of injured wheat in parts of the state where destruction by snow mold is rarely seen, said WSU plant pathologist Tim Murray. He recently met with 20 growers in the town of Prescott, Wash., to address their concerns about the mold’s impact on winter wheat.

“Growers in this area have never seen this mold until now,” he said. “Its presence may have surprised me, but it really surprised them.”

After examining a half-dozen fields in southcentral and southeastern Washington, Murray identified winter wheat damage ranging from nonthreatening lesions on leaves to underground crown decay that kills the crop.

“I was surprised to see how prevalent the damage was in some of the fields,” he said. “We’ll definitely be seeing some economic damage as a result.” He stressed that the extent can’t be tallied until soils are warm enough to reveal which plants could withstand the damage and which could not.

Pink Fungus Among Us
A cold-loving organism that thrives under long periods of snow cover, so-called pink snow mold attacks perennial plants and overwintering crops. It’s more commonly seen in the higher elevations of northcentral Washington where snow blankets the ground for 100 days or more.

But this winter’s pervasive snowy weather fueled the mold’s growth in lower elevations as well, said Murray, including Walla Walla, Whitman and Columbia counties. Caused by the fungus Microdochium nivale, the pink-tinged mold is showing up in fields of winter wheat and even lawns of grass, he said.

“Snow protects winter wheat and other dormant plants from cold temperatures, which is a good thing,” he explained. “But the snow cover becomes a problem when it stays on the ground for too long, which is just what happened.”

In areas where the fungal disease is evident, snow had covered the ground 60-70 days. Although longer than most years, “it’s still not long enough to cause the kind of damage I’ve been seeing. It typically takes at least 100 days,” said Murray.

Why, then, is the fungus among us? Abnormally warm temperatures in November kept the ground from freezing before the first hard snow arrived, creating a more hospitable environment for Microdochium nivale to grow, he explained. That, coupled with a longer-than-usual period of snow cover, gave it just what it needed to thrive.

“The fungus is out there. As we’ve seen, when the weather allows it to take advantage of the situation, it does,” he said.

Growers Advised to Wait
Murray has spent 40 years helping to develop high-quality wheat varieties that mount a defense reaction against snow mold and other diseases that plague the crop in cold climates. Microdochium nivale is one of three fungi that cause snow mold in Washington.

Murray is advising growers to let a few weeks of warmer weather pass in order to assess the full impact of damage in their fields. At that point, they can decide whether reseeding will be necessary.


For questions or comments, contact Tim Murray by phone at 509-335-7515, by email at tim.murray@wsu.edu, or on Twitter @WSUWheatDoc or contact Linda Weiford at 509-335-7209 or linda.weiford@wsu.edu.

White Paper: Strategies to Reduce Economic Losses Due to Low Falling Number in Wheat

The White Paper was developed after the recent Falling Numbers Summit in Spokane, WA on Feb 16, 2017. That event was unique because it brought together a wide group of members of the grain industry, including federal and state grain inspectors, elevator operators, grain millers and bakers, the research community, grain commissions and grower groups, exporters and state extension services and representatives from private sector agronomy and plant breeding companies.

Since 2011, low falling numbers have cost western farmers millions of dollars. Economic losses to the grain industry in 2016 alone exceeded $30 million at harvest and will likely approach $140 million in total. The two causes of low FNs in wheat grain are: 1) pre-harvest sprouting or germination on the mother plant due to rain before harvest, and 2) late maturity alpha-amylase (LMA) due to heat or cold shock during grain development.

At the meeting, the members of the grain community shared current knowledge, determined where more knowledge is needed, developed priorities for action and assigned leaders to each priority action item. The focus of the meeting was on short (3-6 month) and mid-term (6 months to 2 years) strategies. The white paper identifies the strategies and outcomes from that meeting. The immediate goals are to improve the Falling number test by increasing the standardization of the testing protocol and to analyze existing data to detect patterns in the response of wheat varieties.  All results will be posted on the Small Grains Grain Quality Resources page.

A follow-up meeting for researchers will occur at the Western Wheat Workers Conference in Corvallis, May 31-June 1 and a follow-up meeting for the industry will occur at the Tri-State Grain Growers Convention in Spokane in November 2017.


For questions or comments, contact Kimberly Campbell at (208) 310-9876 or at kim.garland-campbell@ars.usda.gov.

Stripe Rust Update – March 2017

Dr. Chen, USDA-ARS Research Plant Pathologist in Pullman, and the Oregon State University Variety Testing and Plant Pathology Team (Mike Flowers, Larry Lutcher, Christina Hagerty and Chris Mundt) each released disease updates (Dr. Chen’s report and the Plant Pathology’s report) during the past week.

Using six different models based on air temperature, Dr. Chen is predicting this year’s stripe rust epidemic will be more severe than his first prediction in January.  Although air temperature during several periods in December and January was below the 5°F threshold for survival of the stripe rust fungus in plants, most of the wheat-growing area in eastern Washington had a blanket of snow cover that protected both winter wheat plants and the fungus, allowing both to survive. Consequently, Dr. Chen is now predicting an epidemic with potential yield loss of 32% on highly susceptible varieties, compared to 6% in his January forecast. Dr. Chen also reported finding actively sporulating stripe rust pustules during the week of March 6 in Walla Walla County where the wheat has greened-up and started growing. Fields farther to the north in Adams and Lincoln Counties were either still under snow or, where snow was gone, had dead spots where rust infection was severe last fall, or fall-infected leaves were dead. It is possible that the stripe rust fungus is still alive in these plants and may begin to sporulate once the plants begin growing again. These observations were confirmed in the OSU report, and stripe rust was observed on several varieties at two variety testing locations (Lexington, OR and Walla Walla, WA) and appears to be widespread in eastern Oregon and southeastern Washington.

Going forward, it will be important to scout all winter wheat fields and consider using a fungicide with herbicide application if the variety is moderately susceptible or susceptible (rating of 5 to 9) or active stripe rust is found on 2-5% of the plants in a field. Continue to monitor fields throughout the spring, especially as the end of fungicide effectiveness nears (3 to 5 weeks, depending on the fungicide).  For spring wheat, plant the most resistant variety available, preferably those rated 1 to 4.


For questions or comments, contact Dr. Chen at xianming@wsu.edu or (509) 335-8086 or Tim Murray by email (tim.murray@wsu.edu), by phone (509-335-7515), or Twitter (@WSUWheatDoc).

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