Onion seed-Thrips

Includes

Onion thrips (Thrips tabaci)
Western flower thrips (Frankliniella occidentalis)

Pest description and crop damage Adults are small, slender, feather-wing insects. They are yellow to light brown and about 0.06 inch long. The young are wingless. They feed on foliage, reduce plant vigor, and may kill tops.

Management-chemical control

Onion thrips are not damaging once seed heads have formed. Western flower thrips, which feed on pollen without damaging seed, often are most prevalent in the flower heads. It rarely is justified to treat for thrips beyond the initial early application.

  • azadirachtin (Neemix 4.5) at 10 to 12 fl oz/a (0.031 to 0.037 lb ai/a). PHI 0 days. REI 4 hr. In most cases, apply at high rate. This botanical pesticide acts slowly. Repeat in 7 to 10 days as needed. Spray early and check for effects. Some formulations are OMRI-listed for organic production.
  • spirotetramat (Movento) at 5 fl oz/a (0.08 lb ai/a). Apply no more than 10 fl oz/a (0.16 lb ai/a) per crop season with a minimum treatment interval of 7 days. For onions, leeks, and chives grown for seed production, do not apply 4 months prior to bloom, during bloom or until after petal fall.
  • spirotetramat (Movento HL) at 2.5 fl oz/a (0.08 lb ai/a). Apply no more than 5 fl oz/a (0.16 lb ai/a) per crop season with a minimum treatment interval of 7 days. For onions, leeks, and chives grown for seed production, do not apply 4 months prior to bloom, during bloom or until after petal fall.