Spider Mite treatment

Maarten van Helden Maarten.vanhelden at medew.ento.wau.nl
Mon Jan 30 08:47:53 EST 1995


In article <3g61d6$6ts at news.primenet.com>, flchris at primenet.com (Frank Christ) says:
>
>I have spidermite infestation on a house plant. So far I have tried 
>wiping each leaf and stem with cotton dipped in rubbing alcohol.  There 
>seemed to be some improvement, but now they're coming back.  Any ideas?
>
>--
>flchris at primenet.com       "The illiterate person is not one who cannot read,
>Frank L Christ              but the person who has not learned to learn"
>Emeritus, CSU Long Beach               [Freely adapted from Gujuoy]
>
Well, spider mites are quite easy to treat, if you can get the best natural enemy for
biological control that is available: the predatory mite phytoseiulus persimilis.

It is in use here in holland since more than twenty year and the results in greenhouses
are so good that almost 100% of the growers uses it nowadays. I used it
on some of my house plants and indeed, the spider mites are completely extinguished.

In greenhouses the spider mites form patches of infested plants, once a prdatory mite has
reached such a patch the population is doomed. However some spider mites will escape
(transported by winds) and found new colonies. Once the primary colony is completely
wiped out by the predatory mite they also will start to migrate (and possibly find the
new colonies). The overall results is a very low density of very small colonies of spider mites
which are easily controlled by the predatory mites at a level far below the economic threshld
for this pest.

If you can't get the biological control agent: Put the plant outside (when it is warm enough) 
almost any pest will disappear outdoors.


Maarten van Helden 



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