Sacha writes
On 2009-10-02 16:07:15 +0100, K said:

Sacha writes
Kay, I asked Ray about this and he'd had identical experiences
many years ago when using a compost which contained something that
killed off vine weevil but unfortunately, it also killed off the
predators. He can't remember the name atm but I'll post it if and
when he does! For quite a long time the makers denied this but in
the end, so many people remarked upon it that they had to admit it
should not be used where biological control predators were being
used. So he wonders if you've been using something similar.
I haven't changed my compost between .3 years ago when I got good
control and the last three years. I use New Horizon.

And it does have anything added to it to control vine weevil -
something Green, IIRC. It's one of those names that just will not stay
in my head!

No mention in the data sheet of added pest control. Are you sure that it
does? If so, I'll have to ask the manufacturer about it. I'm inclined to
think not, else I wouldn't have had success with the predator in better
years.



However, the pesticides get onto e.g. plastic pots and that holds a
residue for rather a long time. I have at the back of my mind some
experiment or other that Ray carried out - or found out about - I'll
try to remember to ask him about it.

Again, that's something I'd expect to happen every year, but it is worth
investigating.


In sunny Leeds - perish the thought. ;-) i.e. Probably!
I still have a few predators - the odd cocoon type thing here and
there, so slow breeding seems the most likely.

Of course, once the predators have eaten all the nasties, they, too,
will die off so you may have to start again next year.

That's not a problem that I've had in the last three years ;-)
--
Kay