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Old 08-06-2003, 01:32 PM
jane
 
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Default Biological control of caterpillars

On Sun, 8 Jun 2003 12:50:15 +0100, Chris ] wrote:

~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?

That's what I use. I've gone over to doing my planting in rectangular
1.5ydx3.5yd plots rather than rows, so it's easier to net stuff that needs
it.

I put a wooden post (1.5"x1"x2' with 6" below ground) at each corner of the
plot, a cane with cane top in the centre (slightly higher) and an old plant
pot on top of each post. The boxes of green plastic 1cm netting you can get
will do two plots this size if you get the biggest box. Then use 2mm
diameter galvanised wire to peg it down every foot or so rather like a bed
with hospital corners. ( I tend to use 15" lengths of wire bent into an
elongated U, which means they're easy to grab and pull out to do hoeing
etc.)

If you stretch tightly over the posts you don't need to put canes between
post tops to keep the net clear of the brassicas. Make sure there are no
floppy unpegged gaps or the pigeons will get in!

The other nice thing is that if you peg down firmly enough then larger
slugs and snails can't get in either. The only trouble I get is flea beetle
and I have learned to grab the derris quickly...


--
jane

Don't part with your illusions. When they are gone,
you may still exist but you have ceased to live.
Mark Twain

Please remove onmaps from replies, thanks!