cabbage white invasion

[Gavin1]

Hiya, I wonder if anyone can help
I've got an allotment with my father-in-law i've had for a year now and have had a lot of problems with cabbage white and cabbage moth butterflies. We've got quite a large brassica patch and netted part of it this year but this wasn't ideal as it was difficult to keep weeds etc. tidy. I've looked at two products; pyrethrin and bifenthrin but not sure which is better or if there's a better alternative
I wondered if anyone knows the best thing to combat those pesky butterflies

[SarzWix]

I think you'll be hard pressed to find anyone on here that reccommends an insecticide as a solution
There is a new biological control for caterpillars that might be worth trying? Apart from that, seems like you need to sort your netting out so that it's easier to get on and off for weeding, try buiding a frame and staple the net to it? Or plant through paper or cardboard to suppress the weeds.

[zazen999]

Yup, plant through cardboard and use nets [curtains rather than 10mm nets] and it keeps them nice and clean.

[rustylady]

Netting is good - protects brassicas from butterflies and pigeons, but it does need to be small mesh. I use my netting in small areas as I only grow a few brassicas, it's easy to lift for weeding etc, and it does help if you don't grow all your brassicas in one area - bit like McD for butterflies etc.

[Sue]

Hi
I have found another approach - I had a big bed of tuscan kale and the butterflies kept squeezing in and I couldn't keep up with caterpillar squashing. The result was that I had a bed of what looked like umbrella ribs.

By the time I got around to clearing my umbrella ribs I found they were all sprouting tiny new leaves so cut off all the ribs and awaited developments - now have full heads of kale again. I tried this with the cabbages and as long as the hearts are undamaged they will regrow too.

Not a good method if you want your brassicas at a certain time but if you're prepared to wait then they should regrow.

The other benefit is that the kale leaves are now too high for the pigeons!

Sue