- Pest Type: Insect
- Crops Affected: Cotton, Wheat, Soybeans, Corn, Peanuts
- Scientific Name: Limothrips cerealium, or Frankliniella spp.
- Pest Order: Thysanoptera
Adult thrips are only 0.4-1.5 mm long and are various colors. These adults which are slender, torpedo shaped, fast-moving, and agile, generally have 2 or 4 wings. Eggs are usually oblong and a creamy color. Larvae are very small; i.e., about 0.25 mm long; and are white or cream-colored during the first instar, gaining more color during later stages. There is a prepupal stage and a pupal stage that occur in the soil.
Both immatures and adults feed by rasping the buds and 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. Thrips can also transmit viruses. Thrips are almost always present in a soybean field, but during outbreak years they are noticed and cause concern. In particular, during dry weather and on earlier planted soybeans, thirp populations may soar when plants are growing slowly. Thrip injury on soybeans nearly always occurs early in the growing season and especially under dry conditions.
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 instars before entering the soil to pupate. Adults are active from mid-May through September. Under favorable conditions, a complete life cycle may require only two weeks.
When economic thresholds are reached, thrips can be controlled with insecticides; however, thrip populations usually do not justify insecticide treatments. Still, when infestations are significant, contact local advisers for thresholds and control information.
Several species of thrips feed on small grains across the United States, and in Canada and Mexico.