The predatory mite, Californicus is proving a valuable tool in the battle to conserve sprays and delay the development of miticide resistance.

Initial interest in Californicus came from industries such as strawberries, rubus crops and greenhouse production said David Loxley, tree crop specialist at Bugs for Bugs.

Since then there has been an increase in use across a range of tree crop industries, particularly apples and stone fruit. Bugs for Bugs has been rearing them for more than eight years.

“Californicus (Neoseiulus californicus) are aggressive and robust predatory mites that feed on a range of pest mites, including two-spotted spider mite (TSM),” Mr Loxley said.

“They tolerate a wide range of environmental conditions and can be used in situations where other predatory mites may struggle. Adults can consume five adult spider mites per day, and at 30°C they complete their lifecycle in four days (twice as fast as TSM).

“TSM is one of those insidious pests that has the potential to cause considerable damage quickly. TSM infestations can lead to poor production, poor fruit colour development and generally poor tree thrift.”

Mr Loxley said the population dynamics of TSM infestations can vary considerably across locations, seasons, and spray programs. “Knowledge of the chemistry being used in crop production is critical, because Bugs for Bugs staff may be able to suggest improvements to product selection and timing.

“Manipulation of spray programs can have a dramatic effect – supporting better establishment of the Californicus and countless naturally occurring beneficials that help to control mites and other pests.”

Mr Loxley and his team have been successful in developing a number of IPM programs across a range of crops in Australia. The TSM challenge to pome and stone fruit production requires planning, but also timeliness of response.

“Even though Californicus is a naturally occurring predator of TSM, by releasing it we are fast tracking its natural build-up in order to achieve a more acceptable commercial outcome.

“Californicus can survive by feeding on pollen. This allows for early releases before many TSM are present in the crop. This feeding ability, alongside the ability to survive within a wider range of weather conditions provides us with a flexible management tool.”

Growers have welcomed the availability of Californicus. Some have been motivated to get involved in the development of various machine applicators. Whilst the option of hand-applied releases is still being utilised, there is an incentive to explore mechanised release technology to save labour and help get the job done in a timelier fashion.

“Drone applications are also an option,” Mr Loxley said. “We have been collaborating with Aerobugs, a company that provides both drone and ground rig application services. We expect this will make predatory mite releases even more appealing to growers that are considering adopting IPM or looking to enhance their existing IPM programs.”

Mr Loxley said Bugs for Bugs welcomed the involvement of researchers, consultants and reseller collaborators. “Our team is looking forward to helping tree croppers who see an opportunity to use Californicus to protect their crops. We encourage growers to visit our website for more information.”