Choosing The Right Predator For Spider Mite & Thrips

There are now lots of different predatory mites used in the biological control of Spider Mites and Thrips and it can be difficult to know which is the right control to opt for. At Dragonfli we’ve come up with a guide to help you make the right choice.

Two Spotted Spider Mite (commonly known as the Red Spider Mite)

There are three predatory mites available for the biological control of Spider Mite. A recent study conducted by Koppert Biological Systems compared the reproduction speed of each predator and how quickly they controlled Spider Mite infestations. The study found that the fastest to reproduce and control Spider Mite was the Phytoseiulus persimilisThis is the predator we use in our Spider Mite Curative System. Choose this predatory mite if you are already suffering from a clear Spider Mite infestation and temperatures are above 20. The Phytoseiulus provides a faster control of Spider Mites and will attack Spider Mite in their webs and webbing, unlike the Amblyseius andersoni which will not enter such areas of infestation. This makes the andersonibad choice of Spider Mite predator if you already have spider mite present in high numbers.

The next fastest establishing predator found in the study was the Amblyseius californicus (also named Neoseiulus californicus). This is the predator we use in our Spider Mite Preventative System. This predator establishes quickly on the plant and will also go into Spider Mite webbing. It can be supplied in slow release sachets, which makes it ideal as a preventative treatment for Spider Mite. Amblyseius californicus will also feed on other mites and pollen, enabling it to live on plants when no spider mite present. Phytoseiulus persmilis is not yet available in slow release sachets and so must only be released when Spider Mites are present. The two predators can be used successfully together.

One restriction in the application of Amblyseius californicus is that it is not yet permitted for outside use. For Spider Mite control outside in the summer, when it is warm, use Phytoseiulus persimilis. For preventative treatments outside, when it is cooler, use Amblyseius andersoni .

Thrips

The predatory mites available to control Thrip will only consume the larvae of the thrip, unlike certain Spider Mite predators which essentially eat the entire Spider Mite life cycle. For this reason it is important to apply Thrip predatory mites to plants as early as possible so that they have a chance to break the Thrip life cycle. In the same way as the Spider Mite predators, there are now a few Thrip predators to choose from. 

The first predator used for Thrip control in greenhouses was the Amblyseius cucumerisIt is still widely applied as a preventative and curative control of Thrips and is normally the cheapestoption. It is active from 15 and consumes the first, very small, Thrip larvae, so you do need a good population of predators present on the plant. For preventative applications opt for our slow release sachets which will release predators for approximately 4 weeks. To build up and spread a population quickly over leaves opt for a shaker bottle application and then follow this up with sachet introductions.

In recent years another predatory mite has been added to the armoury against Thrips in the form of Amblyseius swirskii. This predatory mite also eats Thrip larvae but is capable of eating larger bodied larvae, so is capable of consuming more Thrip larvae overall. The swirskii will also feed on Whitefly eggs. It requires temperatures of 20 plusto be active. A good application strategy can be to start Thrip control with Amblyseius cucumeris, especially if temperatures are lower, and then switch to Amblyseius swirskii once temperatures are over 20℃. Amblyseius swirskii are also available in foil sachets which provide extra release life, whereby predators are produced for up to six weeks.

Choosing the right predator is very important to get the best results from your predatory mites and we hope this guide has helped you to make the right choice. 

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