Controlling apple mite pests in Israel using augmentative releases of Neoseiulus californicus and naturally occurring Typhlodromus athiasae

Abstract: Apples in Israel are attacked by four main mite species – Tetranychus urticae, T.
turkestani, Panonychus ulmi and Bryobia rubrioculus. Growers typically control these mites by combining chemical acaricides and naturally occurring predators, mainly the predatory mite Typhlodromus athiasae and the lady beetle of the genus Stethorus. To test whether commercial augmentative biological control can replace chemical control and whether it can be combined with the naturally occurring predators, we conducted a series of field trials. We tested the establishment of predatory mites and the control level when using commercial products of N. californicus. Four commercial apple orchards used as study sites, in which we compared the application of a slow release sachet to an untreated control. In one study plot we also tested the application of N. californicus through an air blower. Results varied between study sites: while the pest mites were successfully controlled in all trial sites, in two sites the predatory mites’ community was dominated by the local T. athiasae and the other two sites showed a higher establishment of N. californicus. The main pest in the sites in which N. californicus became the main predatory mite were mites of the genus Tetranychus, and the other sites were dominated by P. ulmi and B. rubrioculus. Better suitability of N. californicus to the dense webbing created by Tetranychus mites, and their high reproductive rate, may explain why it became dominant over T. athiasae in the study sites in which Tetranychus mites were the main pest, but not in the others. These results are discussed in the context of using commercially available predatory mites in combination with indigenous ones.