The message ]
from Chris ] contains these words:

In article , Helen
writes
I wouldn't dream of applying any chemicals to potential food. You may
as well spoon it in and see what happens!
The original poster got it right with mesh. If mesh netting is used it
prevents the Large White and Small White butterflies form laying their
eggs. The former produce the speckled yellow, green and black
caterpillars, the latter the green ones. And if there isn't enough
mesh, go out and get some more.

I'll have a go with mesh. What kind of mesh is best?
I've got some thin green plastic stuff with about half-inch holes,
that I use to keep birds off seedlings. Is that OK?
--
Chris


No, you need the white stuff sold under the name of Enviromesh. It has
tiny holes and acts as a complete barrier, but lets rain through.

As a matter of interest, reverting to the original posting, the
biological control is apparently not going to be available this year
except in commercial quantities. I think it was something to do with
no-one applying for a licence in time. It should be available again next
year.

Janet G