• Pest Type: Insect
• Crops Affected: Soybeans, Potatoes
• Scientific Name: Frankiniella occidentalis
• Pest Order: Thysanoptera

Description
Adult western flower thrips are only 1 to 2 mm long and are yellow or yellow-orange in color. These adults have two pair of fringed wings. Eggs are oblong and are a creamy color. Larvae are very small; i.e., about 0.25 mm long; and are white or cream-colored during the first instar, turning more straw-colored during later stages. There is a pupal stage that occurs in the soil.

Damage
Both nymphs and adults feed by rasping the leaf surfaces with their mouth stylets and sucking up the sap which flows from the injured area. This injury causes distorted leaves with a silvery and/or flecked appearance. The tips of the leaves generally wither, curl up, and die. The western flower thrip also feeds on the blooms of potatoes. Probably more importantly, thrips can transmit viruses.

Life Cycle
Adults overwinter in plant debris, under bark, and in other protected areas. The adults become active in April and May and lay eggs in host plant tissues. Larvae hatch and enter two or more instars before entering the soil to pupate. Nymphs and adults are active from mid-May through September. Under favorable conditions, a complete life cycle may require only two weeks.

Control Measures
When economic thresholds are reached, thrips can be controlled with insecticides; however, western flower thrips can be difficult to control. When infestations are significant, contact local advisers for thresholds and control information.