Western flower thrips, Frankliniella occidentalis, is major pest in greenhouse ornamental plants. This report shows the results of experiments with top layers for predatory mites, banker plants for Orius and a Lure & Infect system for adult thrips.
Top layers consisting of a mixture of bark, bran and yeast increased densities of prey and predatory mites, both in the soil and on the plants. This resulted in a better control of thrips in alstroemeria and roses compared to treatments with predatory mites but without top layers. However, application at highinitial thrips densities could result in a temporary escape of thrips. Pepper plants, amaranthus and cornflowers were suitable banker plants for Orius. The best development of Orius was observed on cornflowers in a no-choice situation, but pepper plants were often preferred by Orius for oviposition when plants were mixed.
The Lure & infect system with Beauveria bassiana was not successful in controlling adult thrips. Only 10 % of the recaptured thrips were infected and no significant effects on thrips densities were observed. Moreover, laboratory experiments showed that infected females continue laying eggs for a few days, which makes this method less effective than killing adults directly after catching them.