With the exception of spirotetramat, chemicals that are used for control of mites on apple are not systemic. Higher volume spray applications to give good cover are needed to get the best results.
- Acequinocyl (Kanemite), clofentezine (Apollo), cyflumetofen (Nealta), fatty acids (Flipper), hexythiazox (Nissorun) and tebufenpyrad (Shirudo) are approved for control of fruit tree red spider mite and/or two-spotted spider mite on apples. Spirotetramat (Batavia) is approved for control of sucking insect pests.
- Clofentezine (Apollo) and hexythiazox (Nissorun) are ovicides. If significant populations of overwintering eggs are present, a spray may be applied up to just before blossom before egg hatch commences.
- It is important to use a high spray volume to thoroughly wet the bark as only eggs that are directly intercepted by spray are likely to be controlled.
- Application is best made in the late dormant period before green cluster as it is easier to get good spray cover before the rosette leaves develop.
- For damaging summer infestations, acequinocyl (Kanemite), cyflumetofen (Nealta), fatty acids (Flipper) or tebufenpyrad (Shirudo) are the available choices.
- The product chosen will depend on other pests to be controlled and the history of previous use of acaricides (see below).
- These acaricides are best applied when most eggs have hatched but before breeding infestations become established.
- Higher volume sprays to achieve good cover are more effective. Tebufenpyrad (Shirudo) should not be applied before 90% petal fall and after bee activity has ceased because of the high risk to bees.
- Acequinocyl (Kanemite) and cyflumetofen (Nealta) are new products and their effect on bees is unknown. Until experience is gained, it is best to wait until 90% petal fall before making an application.
- A full approval for spirotetramat (Batavia) on apples for the control of sucking insect pests will control fruit tree red spider mite, but growers may prefer to reserve its use for more difficult to control pests such as woolly aphid or rosy apple aphid. It must be applied after flowering and works best when pests are moving from brown wood to green tissue. It will prevent population build-up but does not offer pest ‘knockdown’.
- The bioinsecticide fatty acids (Flipper) has an EAMU approval for use on apples. It is effective at controlling sucking insect pests such as aphids, whitefly and mites, so is likely to control fruit tree red spider mite. It is known to complement the use of Batavia as it provides quick ‘knockdown’. Its safety to beneficial insects such as Typhlodromus pyri and the parastic wasp Platygaster demades is unknown, but it is generally safe to many other predators and parasitoids, so is considered to be more suitable to IPDM programmes than the synthetic pyrethroids.
Resistance to acaricides and avoiding its development
- The fruit tree red spider mite readily develops strains resistant to insecticides and acaricides.
- The best way to avoid the development of resistance is to ensure that the orchard predatory mite Typhlodromus pyri is conserved so that acaricide use is unnecessary.
- Acaricides should be used as little as possible, alternating different products to reduce the risk of development of resistant strains.