Establishment of the orchard predatory mite, Typhlodromus pyri, is crucial. Unless the predator is established, regular outbreaks of apple rust mite and fruit tree red spider mite are inevitable and these can be very damaging and difficult and costly to control.
- Once the predator is established and the biological equilibrium between the predatory mite and the pest mite has stabilised, rust mite and fruit tree red spider mite seldom cause problems, providing the equilibrium is not disturbed by the use of pesticides harmful to the predatory mite.
- The predatory mite will establish naturally in apple orchards but this can be a slow process.
- Pest mite infestations are often present and can develop rapidly on newly planted trees which do not have established populations the predatory mite (often because they have been sprayed with predator-harmful pesticides in the nursery e.g. with frequent sprays of fungicides to control canker).
- Where the orchard predatory mite is absent, e.g. in newly planted orchards, it should be introduced in summer by transferring extension shoots from established orchards where the predatory mite is abundant.
- Summer prunings may be used. Ideally, at least one shoot should be placed amongst the foliage in each tree of the orchard where the predator is to be introduced.