"Ian Burns" wrote in message m...
At this time of year, the whole area of our garden under concrete (a
terrace and paved areas) are swarming with what I believe are
Phytoseiulus persimilis, best known as the predator for red spider
mite.
No - not Phytoseiulus persimilis, they are *much* smaller and slower than the little fast moving red spiders that you're
seeing. They are very common in hot dry parts of the garden at this time of year. Absolutely harmless and nothing to get
concerned about. Less concrete/ more beds and borders and of course plants with the moister conditions that these would
bring is the way to reduce your little spiders if you must - you'll have a more interesting garden as well ;-))
BTW Phytoseiulus persimilis if you look at it with a decent hand lens has a somewhat pear shaped body compared with the
round body of these much larger little spiders.

Rod