Wednesday, May 6, 2015

Stripe Rust and Snow Mold Update

Update from Juliet Marshall, University of Idaho Cereal Cropping Systems Specialist and Pathologist.
     1) Dr.David Hole, USU, has found stripe rust in a breeding nursery in Logan, UT. Heading has started. Varieties affected included Lewjain, Lucin CL, and an advanced breeding line. Scouting is recommended throughout southern and eastern Idaho.
     2) Yesterday afternoon I was at the Tetonia Research Station rating winter wheat for snowmold, and I noticed stripe rust on some lines that were from Washington State’s pathology program. I don’t know the line names / pedigree of infected lines. The stripe rust was on both lower leaves and mid-canopy on plants that were late tillering to jointing.
It is possible that the infection overwintered, however I was there April 21, and saw no evidence of stripe rust. The snow mold infections were pretty good, with many of the overwintering leaves destroyed. I think this is an early spring infection (this season). The nursery is being destroyed today, so that should remove the source. However, if I had susceptible lines of spring or winter wheat, I would be spraying fungicides at herbicide application. The current temperatures are conducive to infection, and these localized thunderstorms will assist in spread and the moisture conditions that promote infection. 
Please see the appendices in the 2014 Small Grains Report for last year’s ratings of the spring wheat lines:
Please let me know if you see stripe rust in your area!
Update from Olga Walsh, University of Idaho Cropping Systems Agronomist, Parma Research & Extension Center.
     Stripe rust was identified in winter wheat extension nurseries at University of Idaho, Parma Research & Extension Center - one leaf on one plant only has been affected so far. Scouting will be continued. Fungicides will be applied to contain the disease spread to other areas.


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