Amblyseius (Neoseiulus) californicus
Amblyseius californicus needs a license for release in some countries. It gives good control of spidermites. It should be used in hotter and drier situations where Phytoseiulus has some difficulties to control the pest. It is more expensive to use than Phytoseiulus persimilis and is not required in situations where the latter is already giving good control.
There are a number of acaricides that are compatible with use of Amblyseius californicus, such as hexithiazox. Dried residues of abamectin are not directly toxic, but ingestion of poisoned spider mites may result in death. This compound is useful for cleanup treatments early in the growth of the crop, or towards the end of the crop cycle. Seek advice before using with Sulphur.
Amblyline cal is a product containing the predatory mite Amblyseius (Neoseiulus) californicus (McGregor), Phytoseiidae, Acari. It is a predator of various species of spider mite, including Tetranychus urticae and Tetranychus cinnabarinus. It can also feed and reproduce on other arthropod prey or pollen.
It is supplied as units of 2,000 mites mixed with a carrier material in 125ml bottles and units of 25,000 in 1ltr bottles.
Amblyseius (Neoseiulus) californicus is an active predatory mite that has specialised in feeding on mites in the family Tetranychidae. This includes the common Red Spider Mite or Two-Spot Mite Tetranychus urticae, and the Carmine Mite Tetranychus cinnabarinus. It is less specialised than Phytoseiulus persimilis, and while it prefers to feed on spider mites, it can feed and reproduce on other arthropod prey or pollen. Where few spider mites are present, it is able to survive by feeding on these alternative sources of food, and so can persist in a crop longer than Phytoseiulus persimilis.
Like P. persimilis, it lays eggs in spider mite colonies, and these hatch to produce a six legged larva followed by protonymphal and deutonymphal stages before adulthood. Total development time at 21°C is nearly 10 days, while at 30°C this reduces to 5 days. These figures compare favourably with those for the principal prey Tetranychus urticae, which develops at 16 and 7 days at these temperatures respectively.
Each female is reported to lay an average of 3.85 eggs per day when feeding on Tetranychus urticae, 1.12 per day on Frankliniella occidentalis, and 1.18 per day on corn pollen (Croft, Monetti and Pratt, 1998). The lifetime total per female is reported to be higher than that for P. persimilis, but there are only two females to every male, rather than 4 females to every male for P. persimilis. Overall egg production by a population will therefore be lower than for P. persimilis.
Laboratory studies, and field studies on strawberries in California, seem to show that Amblyseius californicus is a much less effective predator than Phytoseiulus persimilis. It lays fewer eggs, does not search for prey so thoroughly, eats fewer prey individuals and has a lower rate of population growth. Nevertheless it is regularly found in the same fields as P. persimilis, and is reported from various glasshouse and field crops to persist for longer and to control spider mites in situations where P. persimilis does not work well. These include hot, dry conditions and ornamental plants where the density of spider mite is low. It is possible that the ability to subsist on other sources of food allows A. californicus to survive for longer and continue searching in situations where P. persimilis would starve to death.
Amblyseius californicus is also reported to be highly resistant to some commonly used insecticides. In crops in Spain, where there is a history of pesticide use, Amblyseius californicus is often the first predator to return to a crop after treatment.
Amblyseius californicus can be used in any situation in which Phytoseiulus persimilis would be used. It is normally recommended for use in conjunction with P. persimilis, or in areas of the crop where P. persimilis has previously failed because of hot dry conditions. On specific crops it may be recommended alone, where trials have shown it to be effective.
Amblyseius californicus is more expensive than Phytoseiulus persimilis, and is not recommended for use in crops where the latter predator has previously given good control. It should not be used as the sole means of control where there are heavy outbreaks of spider mite. Use a compatible acaricide such as hexithiazox or bifenazate to reduce spider mite numbers before releasing predators in this situation. Alternatively, a strategy using Amblyseius andersoni early in the crop to suppress initial outbreaks of spider mite populations may give adequate control leaving only occasional hotspots requiring an additional release of Amblyseius californicus or Phytoseiulus Amblyseius californicus or Phytoseiulus.
Note also that Amblyseius californicus is not native in the United Kingdom, and may be released only in glasshouses, under licence from DEFRA. Restrictions apply concerning the types of crop and areas of crop on which it may be released. Consult your supplier for the latest information.
Amblyseius californicus will control outbreaks of spider mite when used as directed. It should always be used preventively, while spider mite populations are small.
Amblyseius californicus will not control large outbreaks of spider mite except at high release rates. Use a compatible chemical in this situation. Amblyseius californicus feeds on a wider range of prey than P. persimilis does and there is evidence that it will control other mite pests such as Tarsonemid Mites). It is recorded from fruit trees infested with the European Red Mite Panonychus ulmi, and may contribute to the control of this pest.
There are a number of acaricides that are compatible with use of Amblyseius californicus. Examples are hexithiazox or bifenazate. Dried residues of abamectin are not directly toxic. This compound is useful for cleanup treatments early in the growth of the crop or towards the end of the crop cycle.
There are indications that regular use of elemental sulphur as a fumigant against powdery mildew and other diseases causes serious suppression of populations of Phytoseiid mites, and can lead to outbreaks of spider mite. Reducing the frequency of use and ensuring that Phytoseiulus persimilis or Amblyseius californicus are established before first use may limit this suppression.