Winter molds, fungus concern farmers

The negative side of having snow on the ground for a record number of days is the emergence of snow mold, a fungus that thrives in a cold, dark environment. Harsh weather also encouraged the growth of another fungal disease, stripe rust, which is airborne and so spreads easily.

“There’s nothing we can do for snow mold. The plants have to recover on their own, which can set back growth,” said Flowers.

This week, he travelled from Corvallis to the OSU trial plot just north of Dufur to check on the progress of 100 varieties of wheat.

He said soft winter white is the most commonly grown variety in Wasco and Sherman counties. Now that the weather is warming up, he said snow mold has lost its hold on plants and he doesn’t anticipate much damage to the yield.

The exception to that forecast, said Flowers, could be plants in areas that were shaded and retained the snow pack for longer.

Four different snow mold diseases, all caused by soil-borne fungi, can be found in the Northwest.

Flowers said pink snow mold, named for fungal growth that turns a salmon color, is the most widespread of these diseases. The organism destroys the leaves and crowns of host plants.

Having plenty of moisture in the ground should help wheat catch up on growth slowed by plants battling the mold, he said.

The problem with stripe rust is a more serious matter, said Flowers. He said some species of wheat are more resistant to the fungus than others, but most will require the application of a fungicide to stop its spread.

The rust pathogen utilizes water and nutrients from the host plants, which can dry them out quickly.

“It basically uses the plant for energy,” said Flowers.

The germination process for rust requires moisture and it thrives in humidity. The disease can also infect grasses and barley, with symptoms that first appear as chlorotic patches, or stripes, on leaves. Next to develop are tiny yellow to orange colored rust pustules called uredia. Each uredium contains thousands of spores that can float on a breeze.

Although Flowers is an associate professor at the university in Corvallis, he takes regular trips around the state to 19 trial plots to conduct research that will assist Oregon’s agriculture industry in the challenges of food production.

Every two weeks or so, Flowers arrives in Dufur to see what is going on with wheat grown grids on a little more than one acre. In addition to soft white, there are also hard red and hard white species.