Cabbage Root fly collars. Info please!!!

[anto]

We were advised to make cardboard collars to put around our young cabbage plants to keep the beastly root fly off. How tight to the young stem does the collar need to be? How tight a fit? Won't a very tight fit damage the young stalks as the grow and fatten? How long do they need to be there? What is prime root fly attack period?

[dexterdoglancashire]

Hi anto. Not sure of all of the answers to your questions, but you can either buy these or make your own.
I've just made some from some left over roofing felt. I've made them around 2" square and then cut a small cut into the centre.
If necessary, I'll double check when I fit them at the weekend, but last year the ones I used were ready made ones and they were very similar to the ones Ive made this year. Had no probs with pests.
Good luck. Bernie aka DDL

[anto]

Thanks Bernie. Look forward to hearing about them. I'm most concerned about how closely they're supposed to fit to the young cabbage stalks.