Population Dynamics of Thrips and Development of an Integrated Pest Management Program Using the Predator Franklinothrips vespiformis

The thrips Frankliniella occidentalis (Pergande) and Thrips tabaci (Lindeman) (Thysanoptera: Thripidae) are among the major pests in rose greenhouses in southern France. For integrated thrips management, the predator Neoseiulus cucumeris (Oudemans) (Acarina: Phytoseiidae) is available as a biological control agent, but it is not always efficient enough in case of heavy contamination of rose crops by the thrips. In this context, we tested the effectiveness of another predator, Franklinothrips vespiformis (Crawford) (Thysanoptera: Aeolothripidae) against thrips. The experiments were performed in an insect- proof rose greenhouse (576 m(2)). The efficiency of the predator F. vespiformis was tested in combination with N. cucumeris and compared to N. cucumeris alone while the thrips population dynamics in the rose greenhouse were monitored. The combined use of F. vespiformis (5 adults per m2) with releases of N. cucumeris during the periods of heavy infestation gave better results than when using N. cucumeris alone; these results were observed both against adult thrips and larvae. Our results point at the importance of combining various natural enemies against thrips in rose greenhouses, and their implication for Integrated Pest Management on roses are discussed.