Removing barberry bushes stops the fungus from developing near wheat fields, said Diana Roberts, regional extension specialist at WSU's Spokane County Extension.
Over the past year, warm, wet summer conditions have led to stem rust outbreaks in Stevens, Spokane and Whitman counties and beyond, affecting 20 to 100 percent of the plants in a field.
The Washington Noxious Weed Control Board
recently listed common barberry as a Class C noxious weed, beginning in 2013.
This allows researchers to educate growers about the plant, Roberts
Counties will decide whether to enforce the barberry eradication rule.
It will become the landowner's responsibility to remove barberry bushes as they occur, she
"We do not want to be a nursery for new races of stem rust that are going to affect late-developing wheats in the Midwest," Roberts
recommended looking at the fungicide label to ensure applications are legal.
The researchers have found success cutting down the trunk of the barberry bush, applying the herbicides picloram or imazapyr onto the stumps with a crop oil or applying imazapyr to the leaves.
Picloram is not recommended for foliar application because of drift potential.
provided the update on barberry control efforts during the Spokane County Crop Improvement Association
annual meeting in Airway Heights, Wash.