Efficacy of RADIANT (Spinetoram) Against Western Flower Thrips in Romaine Lettuce

Abstract

RADIANT, a new 2nd generation spinosyn insecticide has recently been introduced to the vegetable industry that has shown excellent activity against western flower thrips in lettuce. Several studies were conducted over 2 growing seasons at the Yuma Ag Center to evaluate the efficacy of RADIANT against thrips in romaine lettuce. Three trials were conducted in spring lettuce under moderate and heavy population pressure, and two fall trials were conducted under low to moderate thrips pressure. In each study, RADIANT performed statistically comparable to or better than Success for control of thrips, but at lower use rates. It appears to provide better residual activity against larvae than Success and the standard compounds presently used, but does not appear to provide any additional adult efficacy. RADIANT will be an excellent addition to our IPM programs, however because it has the same mode-of-action as Success, it will not provide an additional rotational partner for our resistance management programs.