Cool temperatures affecting high temperature adult plant resistance to stripe rust

Cool temperatures affecting high temperature adult plant resistance to stripe rust

Farm and Ranch June 8, 2010 USDA Agricultural Research Service scientist Xianming Chen has issued an urgent alert for wheat growers in eastern Washington, eastern Oregon and northern Idaho regarding stripe rust. Chen says in the past week there were many reports of stripe rust in the Pacific Northwest, except southern Idaho. He says stripe rust has been found as far north as near Davenport in Lincoln County Washington. Severity levels range from low to significantly high depending upon varieties and location.

Once again the frequent precipitation in the past two weeks have created the most ideal conditions for stripe rust infection and Chen says in the next two weeks rust severities will increase rapidly on susceptible varieties. The ARS scientist says this spring’s cool temperatures have also affected the adult high temperature resistance of normally resistant varieties.

Chen: “When the temperature is low, just like the last few weeks, this type of resistance is not fully expressed.”

Chen says varieties with moderate levels of high temperature adult plant resistance may need to be sprayed with fungicides. He points out that because most labeled fungicides can only be used before flowering stage and the winter wheat crop has reached boot to flowering in the region, the next two weeks will be critical for stripe rust control. Chen says check your fields and apply a fungicide if necessary.

I’m Bob Hoff and that’s the Northwest Farm and Ranch Report on Northwest Aginfo Net.

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