This aggressive and robust predatory mite is tolerant of a wide range of temperature and humidity conditions and is used widely overseas as a powerful biological control agent. Californicus is able to survive well even at low prey densities due to their ability to use alternate prey and pollen as a food source.
The video clip below was captured recently under the microscope. It is not easy to capture action like this but very satisfying when one does. In this example a californicus predatory mite stars by seeking out and actively feeding on a spider mite egg for the camera.
Californicus feed on a range of pest mite species including:
- two spotted spider mite – Tetranychus urticae
- broad mite – Polyphagotarsonemus latus
- cyclamen mite – Steneotarsonemus pallidus
An adult female predatory mite can consume more than five spider mite eggs per day.
Californicus mites are tolerant of a wide range of climatic conditions and can be used at times where other species may struggle. They can work in harmony with Persimilis to manage a difficult situation. Neoseuilus californicus prefer humidity of 60% or higher and a temperature range of 16-32°C. It is important that the crop is well watered and in a good state of health to ensure best conditions at the plant surface where the mites are active.
Check prior history of chemical applications to ensure toxic residues are no longer present. Some chemicals have a long persistence and this will need to be considered. Generally high temperatures, exposure to ultra violet radiation and rainfall will accelerate the degradation of harmful poisons. Chemicals vary widely in their toxicity to these predatory mites so you should check with us if unsure.
It is always best to commence releases of biological control agents before you have a serious pest problem. Ensure the crop is well watered and in good health as much as possible as this will aid establishment.
For established infestations of pest mites release at 10-20 predatory mites per sq metre three times at intervals of 1-2 weeks depending on the pest pressure.
As a preventative measure release at 5-10 predators per sq metre three times at two weeks apart.
Monitor the population of pests and beneficials at least weekly. The number of predatory mites released and the interval between releases can be adjusted to match perceived pest pressure, rate of build-up of the predators and prevailing conditions.
An ongoing regular release program may be warranted in dynamic environments where plant movement occurs regularly or other influences (such as fungicides) may adversely impact the predators.
A note on release rates: Unlike chemicals which generally exhibit a clearly defined dose response curve, with beneficial insects, more is always better. However, they are costly to produce and the goal should be to achieve the best results at minimal cost. We are constantly trying to strike a balance between cost and efficacy. There are many factors that should be considered including the value of the crop, the magnitude of the pest population and the activity (or otherwise) of naturally occurring beneficial species. Also unlike chemicals, where it is common to respond to pest populations that have already exceeded some ‘economic threshold’, we recommend establishing beneficials early in the life of the crop before pest populations reach threatening levels. In most cases our releases are inoculative and we anticipate that our beneficials will establish and breed up within the crop to give long term control. As a general principle, 2-3 releases of modest numbers is better than a single large release – this reduces risk, improves establishment and accelerates the development of multiple overlapping generations of the beneficial species.
Cultural conditions to aid establishment
- Ensure the plants are well watered and in good health
- A relative humidity of at least 60% is best for californicus mites
- If necessary consider additional wetting of floor and bench areas (in protected cropping environments) to improve the conditions required for successful establishment
- Avoid the application of any pesticides for at least three days after release if possible
Many pesticides may harm these predatory mites. However there is a wide range of materials that are relatively benign. Call us if you are unsure.
Try to keep the application of any pesticides to a minimum. There is now a wide range of beneficial insects and mites that may be used to manage other pests to help you achieve this goal. Try to avoid chemical treatments for at least one week before and after release – even longer if possible.
It is generally best to release the predatory mites as soon as practicable after arrival. However they do keep quite well for several days if conditions are not suitable for immediate release.
If storage is required keep at 10-20°C for up to five days.
Eggs are oval and larger than spider mite eggs (which are round).
Life stages (at 25°C)
- Egg: 2 days
- Larva: (non feeding stage) 0.5 day
- Protonymph: (first feeding stage) 1.5 days
- Deutonymph: (second feeding stage) 1 day
- Egg to Adult: 5 days
- Pre-oviposition period: 1.5 days
At higher temperatures the rate of reproduction will increase up to around 35°C beyond which it stops.
Mites can survive short periods above 40°C
Source: Wei-Lan and J. E. Laing, Biology of Amblyseius (Neoseiulus) californicus, Entomophaga, 1973, 47-60