On 2009-10-29 15:00:37 +0000, K said:

Sacha writes
It's probably enough for you, Kay but I wouldn't know how many to what
area etc.. It's a question of number of houses, variety of plants and
numbers of plants here. But the best thing would be for people to look
at the suppliers' and their advice. We've just done the vine weevil
stuff here and just this morning one of the staff said someone had
given his grandmother a little cyclamen plant (not from here!) which
keeled over and died within two days. Sure enough - there was one vine
weevil grub at the bottom of the pot. ;-(

I think the critical difference is that you need to have a higher level
of pest-free-ness than I do. I can supplement by spraying with water,
inspecting individual plants, removing leaves, physically removing
pests. And I can cope with a low level of pests if I keep them under
control and they're not affecting the plant unduly. There is a limit to
how labour intensive you can be and still be economic, and your plants
need to be completely clean when they go out, not just reasonably clean.

Excellent summation. ;-)

So you will need to introduce predators sufficiently to pretty well
wipe out the prey - and then, of course, you will need to re-introduce
predators. Whereas I can keep enough prey to supply a permanent food
source for the predators :-)

Yes, our objective is total elimination, not feeding 'em!


--
Sacha
www.hillhousenursery.com
Shrubs & perennials. Tender & exotics.
South Devon