Recently, Aaron Esser was interviewed by Scott Yates, director of communications at the Washington Grain Commission for an update on wireworms. In episode 26 of the Wheat All About It! podcast, Esser talks about where we were and where we are today thanks to the great strides WSU researchers have made in understanding and controlling wireworms in Eastern Washington.
Listen to episode 26, Where We Are with Wireworms, and don’t forget to subscribe to the Wheat All About It! podcast on iTunes. Search for Wheat All About It. A summary of podcasts, including many highlighting WSU researchers is available at the WGC website: wagrains.org.
We have received a number of phone calls recently concerning crop damage in peas treated with herbicides containing the active ingredient clethodim. Clethodim is an ACCase inhibitor (Group 1) used to control grass weeds in broadleaf crops. There is no clethodim activity on broadleaf crops like peas. So why is there sometimes injury to peas?
Clethodim products containing 26.4% or 2 pounds of clethodim per gallon (for example, Arrow 2 EC, Clethodim 2 EC, and Select 2 EC) contain as much as 70% petroleum distillates. This high level of petroleum distillates, combined with the required crop oil concentrate and liquid fertilizer additives, can act as a sprayer cleaner, dislodging old herbicide residues that are embedded in tank walls or hoses, resulting in unwanted herbicide residue in the sprayer liquid. It is these residues, and not the clethodim, that are injuring the peas.
This type of damage, which is not unique to clethodim products, can be avoided by properly cleaning sprayers between applications, particularly when changing what crop is being treated. While proper sprayer cleanouts are time-consuming, it can save a lot of money and misery. Removing Herbicide Residues from Agricultural Application Equipment is an excellent publication by Purdue Extension that can help you do a good job of sprayer cleanout and possibly save you headaches and dollars down the road.
Stripe Rust Update June 16, 2017
- Wheat Stripe Rust
In the Pacific Northwest, winter wheat in most areas has passed the flowering stage. Thanks to planting of resistant varieties and widely use of fungicides in the early season with some fields sprayed twice, stripe rust in most fields of winter wheat is under control. Depending upon areas and various times of planting, spring wheat crop varies from Feekes 4 to Feekes 10.5.3. Stripe rust has developed rapidly in spring wheat fields with severity on susceptible varieties ranging from 5% to 100% depending upon area and planting date.
Because the cooler weather and good moisture in this week, stripe rust will likely develop more in the next couple of weeks. For fields of moderate susceptible and susceptible varieties (stripe rust ratings 5 – 9) of winter wheat, fungicide application is needed if the crop has not passed Feekes 10.5 and fungicide was applied more than two weeks ago. For spring wheat, fungicide is needed at the time of herbicide application for fields planted with moderately susceptible and susceptible varieties if not done so. For fields of fungicide applied about three weeks ago, another application is needed. For varieties previously reported to be resistant to moderately resistant (ratings 1-4), check fields and consider fungicide application if active rust pustules are seen and severity reaches 5%.
We took stripe rust notes in our experimental fields of spring wheat on June 15, most plants passed the flowering stage and the susceptible check had 100% severity. Table 1 shows the data and ratings for the spring wheat variety trials for reference. As these data were from only Lind and rust races can be different in different areas, use these data together with the data from the last year for considering to use or not to use fungicides.
Since the last report on May 19, wheat stripe rust has been reported in South Dakota, Minnesota, North Dakota, and New York in addition to the previous reports in Texas, Louisiana, Arkansas, Mississippi, North Carolina, Oklahoma, Kansas, Washington, Oregon, Wisconsin, Virginia, Delaware, Tennessee, Michigan, Kentucky, Nebraska, Indiana, Georgia, Idaho, Arizona, California, Montana, and Colorado. Wheat stripe rust has been reported in Alberta, Ontario, and Manitoba provinces of Canada.
- Barley stripe rust
In our spring crop nurseries at Lind (Adams County, WA), stripe rust was uniform on susceptible varieties with severity up to 40%. For this dryland area, this is the most severe barley stripe rust we have seen in the last 20 years, partially due to the 6-inch higher-than-average precipitation this year, although much lower than wheat stripe rust in this location. Barley stripe rust has not been observed in the Palouse region yet. In addition to Washington, barley stripe rust has been reported in California and Oregon.
Fungicide application may be needed to control barley stripe rust this year. Check barley fields for stripe rust, if severity reaches 5%, apply fungicide. The fungicides that control wheat stripe rust also control barley stripe rust.
Table 1. Stripe rust data of the 2017 WSU Spring Wheat Variety Trials at Lind, WA*
|SY Saltese (SY 04PN3024-2)||SWS||4||2||15||2|
|Ryan (WA 8214)||SWS||15||3||20||3|
|Tekoa (WA 8189)||SWS||17||2||10||2|
|WA 8236 CL+||SCI||18||2||5||1|
|WA 8265 CL+||SWSI||19||5||30||4|
|WA 8266 CL+||SWSI||20||5||30||4|
|AvS (Susceptible check)||21||8||100||9|
|LCS Iron (11SB0096)||HRS||32||2||15||2|
|LCS Luna (10SB0087-B)||HRS||33||2||10||2|
|LCS Buck Pronto||HRS||34||7||30||6|
|SY Coho (04W40292R)||HRS||37||2||5||1|
|SY Selway (04PN3001-2)||HRS||38||2||10||2|
|AvS (Susceptible check)||41||8||100||9|
|WA 8279 CL+||HRSI||58||3||20||3|
|WA 8280 CL+||HRSI||59||3||15||2|
|AvS (Susceptible check)||61||8||100||9|
* IT = infection type; % = severity based on infected leaf areas; and ratings are in a 1-9 scale with 1 for most resistant and 9 for most susceptible.
View the June 2017 Stripe Rust Update in PDF format.
A newly published Extension Bulletin, PNW696, is titled “Integrated Pest Management for the Wheat Head Armyworm Complex in the Pacific Northwest.”
Since 2005, the wheat head armyworm has caused intermittent damage to wheat and barley crops in the PNW.
The two insect species found responsible were initially dubbed the “true” and “false” wheat head armyworms. As these species are closely related, we now refer to them as the wheat head armyworm complex (WHAC).
This publication covers identification, biology, and integrated pest management for WHAC. We emphasize pest monitoring and field scouting methods, and also discuss natural insecticides.
Authors are Diana Roberts, WSU Extension; Silvia I. Rondon, OSU Extension; Peter J. Landolt, USDA-ARS.
In 2016, Washington state wheat farmers experienced widespread problems with low Falling Numbers, for which we created our Grain Quality Resources page. The widespread low Falling Number issue was partly due to Late Maturity Alpha-Amylase (LMA) in response to wildly fluctuating temperatures about one month after pollen shedding. The high temperatures in the 90s on May 30 followed by high temperatures in the 60s has some farmers worried that we’re going to see a repeat of last year’s Falling Number fiasco. Such worries are premature because the wheat hasn’t yet reached the point where it is sensitive to fluctuating temperatures.
It is difficult to pinpoint the window of LMA-sensitivity for this year’s crop because it depends on when the wheat reached pollen-shedding, an event that depends on temperature and varies by variety. Wheat in central Washington reached pollen-shedding during the week following Memorial Day, while wheat further east is just starting to head.
Based on this, we guesstimate that wheat in central Washington may become LMA-sensitive during the last two weeks of June, while wheat further to the east may become LMA-sensitive within the first two weeks of July.