Stripe Rust Found in Goetze, Tubbs

Tanner Sheahan
CPS

Well, I guess I'm the bearer of bad news.  Stripe Rust has been found in Goetze winter wheat in the Willamette Valley.  Monday, March 22, I spotted a small yellow patch while riding my Honda across a nice wheat field in the eastern side of the Valley.
I looked a little closer and discovered advanced stripe rust in the yellow spot pictured above.  At this point, the yellow area is not much bigger than a four-wheeler but I was able to find a few individual pustules starting to show up just outside this area.

Since Monday, your CPS fieldmen have been scouring your fields.  There have been several other Goetze fields in the area, and a few Tubbs06 fields in Benton county, found to be infected with stripe rust.

Generally speaking, according to the calendar, this is pretty early for rust diseases to be showing up here in the Valley.  Refer back to Jason's article on growing degree days and you can see why.  According to the GDD calculator on the Weather Channel website, we have accumulated 64.5 GDD's so far this year since January 1st compared to 7.5 GDD's for the same period in 2009.

Here are the GDD summaries for the last several years for January 1st through March 26th:

2010: 64.5
2009: 7.5
2008: 7.5
2007: 105.0
2006: 29.5
2005: 51.0
2004: 38.0
2003: 51.0

With disease development, the timing of heat accumulation makes a world of difference.  We haven't seen severe disease pressure in our part of the Valley for several years.  As an example, in 2007, only 10 GDD's were accumulated through the end of February with the other 95 GDD's accumulating after the first of March, which was relatively dry.  This year, we have seen 33 GDD's accumulate in January and February followed by a warmer March and a fair amount of moisture. 

What does this mean for Goetze winter wheat production in the Willamette Valley?  Is this just an exceptional year with perfectly timed warming events to spur on disease development?  Is the genetic disease resistance of our two biggest wheat varieties breaking down?  Time will tell but, for now, we're watching closely.  Talk with your CPS fieldman if you are growing winter wheat this year.  It is time to discuss a disease control strategy.