In a subsequent AHDB project - SF 146 "New bio-control agents for Western Flower Thrips on protected strawberry" - managed by Chantelle Jay at NIAB EMR, predators recommended for use on other crops are being assessed for their potential to supplement or even replace Neoseiulus cucumeris in polythene tunnel-covered crops. WFT predators naturally occurring in crops and surrounding habitats are also being studied.
The predatory mites Amblyseius montdorensis, A. swirskii, A. limonicus and the commercial standard N. cucumeris were all effective at reducing WFT numbers at 30/20 degsC day/night temperatures (light/dark ratio of 14:10 hours). Predatory mites were applied to control the larval stages of WFT on the plant and the pupal stages in a strawberry soil-less substrate.
The predatory mites Stratiolaelaps scimitus (formerly Hypoaspis miles) and Machrocheles robustulus both reduced resultant numbers of adult thrips through pupal predation in the substrate. M. robustulus was particularly effective at 30/20 degsC day/night temperatures. Although Anthocoris nemoralis was tested as a predator, this was no more effective than Orius species. Other naturally occurring predators found in crops infested with WFT and surrounding habitats have been identified and will be assessed for their suitability for commercial use during the remainder of the project.