Two insects, one established in the Western United States, the other in the East, have met in Utah to deliver a one-two knockout punch to grain fields in the northern third of the state.
The Western insect is the Russian wheat aphid, first spotted in Utah in 1987. The eastern insect is the cereal leaf beetle, which leapfrogged in 1985 into Morgan County, the first sighting west of the Mississippi River."It looks to me like we're having an outbreak of both insects in the same fields," said Jay Karren, Utah State University Extension entomologist. "In some cases, both insects are causing serious economic damage at the same time."
Areas of greatest concern, he said, are Utah, Salt Lake, Weber, Davis, Box Elder, Cache and Morgan counties.
Karren said he is concerned that if growers look only for one insect, they may overlook the other.
He investigated fields Thursday in Draper and North Logan and found Russian wheat aphids and cereal leaf beetles attacking the same fields in numbers great enough to cause serious economic losses.
Because Utah is the only place where the two insects have met, the insect double-whammy presented Karren with a dilemma.
He said the pesticide Sevin works on the cereal leaf beetle, and Di Syston and Dimetholate work on Russian wheat aphids. But no local research has been done to show whether the pesticides that work on one insect will work on the other. And it's not economical to spray both chemicals.
Thursday, Karren placed calls nationwide and finally tracked down Stan Wellso, a USDA entomologist at Purdue, who told him Di-Syston and Dimetholate work not only on the Russian wheat aphid but also on the cereal leaf beetle, even though the insect is not listed on the label.
Karren added that the cereal leaf beetle is not on the Sevin label either, but he said the chemical has a special "local needs" registration that allows Utah grain producers to use it.