Idaho, USA
February 1, 2012

Stripe rust and fusarium head blight (FHB) were the No. 1 and 2 worst threats in 2011 for southern Idaho wheat growers. Both are expected back in 2012.

Stripe rust fungi produce spores that can be carried thousands of miles in the wind to decimate wheat and other small grain crops in states far from an outbreak’s origins. California, Oregon, and Washington wheat growers are battling stripe rust fungi, which could easily spread to Idaho again.

“I am not as concerned about stripe rust overwintering this year, but it’s likely to be damaging to our spring wheat if it blows in from Oregon and Washington. We’ll have to watch very carefully,” said Juliet Marshall, UI Extension cereals specialist and pathologist based in Idaho Falls and Aberdeen.

Marshall already is busy alerting growers at their meetings and via e-mails about the potential threats, and she is training them in the best ways to battle the problems through timely application of fungicides. She is also seeking computer models to better predict potential threats, especially for FHB, which can be particularly severe following a corn crop rotation. While FHB spores don’t blow on the wind as far as stripe rust, they can still spread locally from infected residue.

Southern Idaho’s usually hot and dry summer weather has protected wheat and grain growers here from stripe rust and FHB for years. But moderate summer temperatures with higher humidity, the increased planting of corn as a rotation crop, and irrigated fields are making southern Idaho grain crops more vulnerable to both stripe rust and FHB.

Corn acreage has doubled to 320,000 acres in 2010—up from 165,000 in 1999, in part because of Idaho’s robust dairy industry. Dairy cows eat corn feed. Planting wheat and barley behind corn increases the risk of head blight developing as Fusarium fungi proliferate on corn residue.

“Juliet’s work is important to keep Idaho wheat growers profitable,” says Director Blaine Jacobson, Boise, Idaho Wheat Commission, representing Idaho’s 4,500 wheat growers. “Millions of dollars of wheat crop losses were averted in 2011 by Juliet’s quick observation and documentation of stripe rust in October 2010,” added Jacobson. “She sounded the alarm and recommended fungicide controls begin in early spring. The outbreak was so severe that some growers saw yield reductions of up to 50%. But wheat growers who followed Juliet’s council limited their losses to a 10 to 20% yield reduction.”

Contact Juliet Marshall at jmarshall@uidaho.edu  see webinars at http://www.idahowheat.org ; stripe rust webinar launches April 4 at 8 a.m. MST.
 

Website: http://www.uidaho.edu

Published: February 1, 2012