Nancy A. Matteson

Range and in-flight densities of barley thrips in the northwest United States.

The barley thrips, Limothrips denticornis, is a new pest in Idaho. Because of economic crop losses attributed to barley thrips in 1990 and 1991, a study was begun in 1992 to determine its biology and life history in eastern Idaho. Suction traps were used to determine in-flight densities of barley thrips during the barley growing season. An extensive tri-state suction trap system was used to delineate its range in Idaho, Washington and Oregon. A suction trap at the Univ. of Idaho, Tetonia Res. and Ext. Ctr., was located within the original area of economic crop damage. Sampling results from this trap were used to monitor the early spring and late summer migration flights of adult females into and out of winter wheat and spring barley. The distribution of barley thrips within the tri-state area included locations where economic losses had not been reported and resulted in new collection records for northern Idaho and Washington. The trap record for northern Idaho was later confirmed in the field.