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3 messages
01/09/2013 at 16:20

Hi All

Any ideas for the control or eradication of Red Spider Mite in my conservatory?

It is only for ornamentals.

Datura, Hibiscus and Bouganvillia.



01/09/2013 at 16:42

Spider Mite - Pests
Commonly asked question(s):

How do I get rid of spider mite? 
What are the little red spots on my Lotus, Black Eyed Susan, Yucca and Gloriosa? 
What are the spider webs on my ginger lilies?

Phytoseiulus persimilis are the most effective control against spider mite. This particular predator reproduces at twice the rate of spider mite. It is highly active under hot dry conditions, where just one mite of P. persimilis can consume 20 eggs or 5 adults per day! However, it requires a minimum temperature of over 16ºC (although daytime temperatures of 21 ºC are preferable) and there needs to be sufficient numbers of spider mite present for the predatory mites to feed on. Obviously, if you choose to use biological control then you cannot also use chemical control as this will kill the predatory mites!

There are a number of cultural practices that you can also use to help prevent and reduce outbreaks. Spider mite thrives in warm dry conditions, so damp down greenhouse floors and paths to increase the humidity. Regular inspection of the undersides of leaves will also help to detect the problem before it spreads. Pick off and burn any infested leaves when you find them. Finally, at the end of the growing season, make sure that you take time to really clean out your greenhouse properly as spider mites like to spend the winter hidden in dry crevices and plant debris until the weather warms up again in spring.

Phytoseiulus persimilis are the most effective control against spider mit
01/09/2013 at 17:27

Having used that predator mite (ie Phytoseiulus persimilis) myself, I can confirm it works.  It's really the only way of completely eradicating red spider mite from a conservatory as they have evolved to be immune to the sort of pesticides we gardeners have available.  SB plant invigorator (which doesn't contain pesticide) will also help to control them by sort of glueing them in place.  In fact, many of the predator suppliers will recommend that you use that a couple of weeks before you introduce the phtyoseiulus.  Not cheap, but they do exactly as it says on the tin (or small plastic bottle in this case!)

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