Cabbage Root Fly

[sewer rat]

Have seen all these articles about this horrible little creature and have a couple of questions so I am able to keep my crops as safe as poss.
1. The collars that you place round the young plants - at what stage do you put these in place and does it matter what they are made of - or are they just simply a barrier ?

2. If the beastie strikes very young plants, would a collar still be required if they were covered with coke bottle cloches ? Would the fly enter through the open top ?

Thanking you all in anticipation

Rat

[Jaxom]

Rat, from what I have seen you can cut a few collars from a single plastic pop bottle. The collars seem to be about 3" high. I'm sorry I can't remember where I saw the photos.
Jax

[Lesley Jay]

We aren't troubled with root fly but you need to put protective discs made out of roofing felt or something similar on the ground around the seedlings. The flys lay their eggs in the spring. I don't know if the coke bottle would work.

[nick the grief]

I have read that you can earth the cabbage up and this will do the trick as well - never tried it as Cabage white are more trouble than fly with me !