Stripe rust explodes in valley

Mitch Lies/Capital Press Oregon State University Extension agent Tom Silberstein at the Marion County Extension Service office in Salem inspects Goetze wheat plants infected with stripe rust.

Cold, wet weather contributes to outbreaks of fungus


Capital Press

SALEM -- An outbreak of stripe rust in Willamette Valley wheat brought on by a cold, wet spring is derailing already prosaic hopes of valley growers -- many of whom were hoping just to break even this summer.

"We're seeing 50 percent yield loss in some instances, where the rust has really hammered things," Oregon State University Cereals Extension Specialist Mike Flowers said.

Flowers estimated valley-wide yields are down 10 percent.

"We have some clean fields out there," he said. "But we have several fields that have completely blown up because the rust got ahead of the growers."

The outbreak in many cases is turning a marginally profitable crop into a losing venture.

"If you budgeted for one fungicide application and you've got to put on two, that can be the difference between making money and not making money," OSU Extension agent Tom Silberstein said.

As of May 20, soft white wheat was bringing only $4.70 a bushel in Portland, about $1.40 below the overall cost of production for 100 bushel-an-acre wheat, according to OSU, and only 90 cents more than direct crop-input costs.

"The problem is it's a marginal crop this year," Silberstein said. "The rust isn't helping."

The outlook for wheat wasn't good when growers planted the crop last fall, Silberstein said, but it was better than the outlook for grass seed, which is experiencing unprecedented oversupply.

Silberstein estimated there are at least 150,000 acres of wheat growing in the valley, about five times more than an average year.

Stripe rust isn't typically a big problem this time of year. The Goetze wheat variety commonly planted in the valley has built-in resistance, which kicks in when temperatures hit 70 degrees Fahrenheit.

This year, however, OSU plant pathologist Chris Mundt said: "We've only had one or two days in the 70s the entire year."

At high pressure, stripe rust saps plants of energy, lowering yields and quality by shrinking kernels. It shows up as yellow streaks on a wheat's leaves and yellow patches in wheat fields.

The rust flourishes in wet, 60-degree weather -- the kind of weather that has permeated the valley this spring. And it had a head start thanks to unusually warm weather in January and February.

By March, fieldmen already were finding the disease, Mundt said, four weeks earlier than normal.

Conditions this spring also are ideal for septoria, another fungal disease that reduces yield by inhibiting kernel development.

"Septoria is splash dispersed, so all this rain is splashing spores up the plants," Mundt said.

"It is a fungus delight this spring," Mundt said.

Adding to complications, growers are having a hard time finding windows of dry weather to get in fields and treat for the diseases.

"That makes it really tough," Mundt said. "On some of the sandier soils, you can get on a field after a couple of days (of dry weather). But on some of these lower fields that are wetter, it's difficult."

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