On 19 May 2004 07:23:09 GMT, Nick Maclaren wrote:

| b)theories of organic gardening re controlling pests with predators (or more
| specifically aphids by ladybirds) is bunk?

Well, I have not seen it work. Ladybirds reproduce fairly slowly
and don't eat huge numbers of aphids, so I am unconvinced that
they make much difference in controlling infestations. Things
aren't as simple as that, because you can also control pests by
restricting sources (e.g. I am spraying my philadelphus with soft
soap now to protect my broad beans later).

While increasing the number of ladybirds and lacewings surely can't hurt, I
bet you'll find that birds take more aphids than ladybirds. Especially when
feeding nestlings. Sparrows and blue-tits appear to take a large number.
Let's face it, they're bigger, need more food and can scoff a lot more in
one mouthful than an army of beetles or lacewing larvae.

I've seen values for lacewing larvae of 300 per larva and 5000 per ladybird
(adult) advertised (in its life, not per day). That might be a lot for a
tiddly little insect but it's peanuts compared to what a tit can polish
off.

--
Tim C.