Winter Wheat Variety Comparisons

The following table combines stripe rust disease readings from the Oregon Statewide Elite Variety trials and yields of those same varieties at the Pendleton/Ruggs and Hermiston sites. I am highlighting only the most commonly planted winter wheat varieties. The complete results of disease notes and yields from the trials are available online at www.cerealcentral.com. It is interesting to note the different levels of infection at the two different sites.

I have included the 2 and 3 year averages when available – realizing that yields were impacted in 2010 and 2011 by stripe rust. 2009 was a year with low stripe rust levels and it is beneficial to include those yields in the average when available.

While weather conditions may return to drier patterns, researchers in Oregon and Washington have noted that stripe rust races have changed and so long-term we will need to respond also. Fortunately, two years have given our wheat breeders an opportunity to do some serious selections for stripe rust resistance but it will take a few years to reap the benefits and bring those selections into our production system.  

My CerealCentral website and August Newsletter provide more in depth information for your planning purposes. Enjoy!!    

Winter Wheat Stripe Rust Infection vs. Yield Comparison, 2011

    

Planting considerations Part Two

I got some reaction to yesterday's posting about which varieties one might steer away from planting because of their susceptibility to strip rust infection. The issue of variety selection is often one of that involves several considerations, but if all other things were equal - one would select the top yielding variety for the area that you grow wheat in. In Umatilla County we have long-term average yields that range from 25 bu. to 90+ bu. and our plant breeders have provided a selection of varieties for these different production areas.

When deciding which variety to plant, if for example you are in a high production area, you would probably want to select the highest yielding variety with the highest level of strip rust resistance. So perhaps you would choose Legion over Tubbs06.


This year, we were able to control the stripe rust through timely treatments with fungicides and it turned out to be a good investment. I don't have hard numbers for the acres treated in Umatilla County, but I estimate that 90% of 250,000 acres were treated once, another 40% treated a second time and maybe 25% treated a third time for a total treated acreage of about 387,000.  Treatment costs varied but even with saving the application costs by tank mixing with herbicide treatments in early spring, I estimate fungicide treatments costs growers about $3.6 million in 2011.

These additional production costs were fairly easy to swallow as prices were good and yield potential was higher than average. If these variables change, which they always do, then the choice might be harder to make.

Let me know where you think we should be headed, but long term I think we will need to look at varieties with higher levels of resistance to the current stripe rust races rather than relying on fungicides. Short term I think we are setup for a possible repeat of last fall with early infections of stripe rust, and we should plan accordingly.
 

Early winter wheat planting considerations

Hopefully, you are wrapping up harvest in the next few days! All reports I have heard have been very positive, so no one is complaining about finishing up late. Yet, with the excellent moisture conditions and the cool night time temperatures, it looks like we will be seeing significant amounts of early seeding in the area.

Early seeding likely faces two challenges this fall. One is aphids and the second is fall infections of stripe rust.

On the topic of aphids, if you are seeding early, prior to October 15^th, an insecticidal seed treatment is your best management tool to prevent aphids transmitting Barley Yellow Dwarf Virus (BYDV). Especially in areas adjacent to irrigated fields of corn, last fall, we saw a migration of aphids to early seeded wheat. Fall infections of BYDV can seriously impact yields. Typically, delaying seeding until later in the fall will reduce the level of infection due to a shorter window of opportunity for aphids to infect the plants. Fall aerial applications of insecticides can be effective, but it is challenging to get the timing right. Always scout your fields before making crop management decisions.

The second challenge that we face this fall is one we have been talking about since the field days in June – the potential for fall infections of stripe rust. Given the high inoculum levels we experienced this past growing season, and the below average temperatures that have continued most of the summer, it is very likely we will again see fall infections of stripe rust in our area.

In our drier parts of the area, the benefits of early seeding still outweigh delaying. The only remaining option is to look at variety selection. The following list, provided by the Mike Flowers and the OSU Cereal Breeding Program, is based on their many observations across the state this past season. These varieties are the most susceptible to stripe rust and should be avoided if possible:

Soft White Winter		Hard Red Winter
AP Badger	AP Paladin
AP Legacy	Bauermeister
Goetze	Esperia
Tubbs 06	Genesi
Xerpha	UICF Grace
	WB Rimrock
	WB Tucson
	Whetstone

Fall application of fungicides for stripe rust control are not recommended as fall/winter environmental conditions may provide some levels of control. It will be important to scout fields, regardless of variety, in late February or early March, depending on growing conditions and weather. If stripe rust is found an application of fungicide is recommended, and can possibility be tank mixed with spring herbicide applications.

Thanks to Mike Flowers, OSU Cereal Specialist, for information he provided for this article.