Cabbage root fly

[pooh]

any ideas on controlling these perishers. I use the collars but it seems to be a waste of time. Although I still get a fairly good harvest of cabbages etc, root fly seem to be at plague proportions on the allotments. Does anyone use anything other than collars around the plants? Pooh

[glallotments]

Somewhere I read (seems to be my favourite quote) that if you leave any weeds growing around the base of the cabbages that the fly can't identify where the stem goes into the ground. Also that they don't like chickweed. We always have chickweed around our cabbages and haven't touch wood suffered from CRF. Probably rubbishy folklore but even if it doesn't work it is a good excuse for leaving the weeds and not having to remove netting which would let white butterflies in. From another angle I guess if you keep weeding that the soil is loosened and makes life easier for the fly.

[Johnboy]

Hi Ken.
If you were to dust the soil at the base of the plant with Derris Dust before fitting the collar. I think this may assist you. Even if you dust the gap between collar and stem very lightly it would help.
JB.

[allium]

As my allot. is heavily infested with club root I dust the base of each plant with builders lime. I am sure this deters root fly.

[Catherine]

We have CRF on our plot every year so last year my OH read something about letting the baby plants get good and strong and larger than you would normally before transplanting. We start ours in small individual cells then transplant into larger pots, then harden them off before planting into the beds where they are to grow. Before we transplant we dig a larger hole than the pot and fill it with compost water the hole well and add dusting of lime, then plant the cabbage into the hole, back fill with compost and water well before putting a collar on the plant. Water the bed well and cover with netting.

We had 98% success with this method. BUT we found you have to keep the plants covered with mesh from seedlings stage right through to when you harden them off otherwise they already have come into contact with cabbage whites and when you plant them under the cover the catterpillars are ready to hatch out and massacre the plants you have nutured so carefully. (Our experience last year) This year has been much better but we still are a work in progress. My Christmas present this year will be a load of Enviromesh (can anyone suggest a reasonable source as we have a large area to cover) and some root trainers which I have found to be absolutely fantastic having used them for two years now. Sorry to have rambled on.

[pooh]

Thanks for the tips, I will try growing (or allow to survive) chickweed, I will also try derris. I have tried putting lime in the planting hole, but that was really for club root which I don't have fortunately. I was beginning to think the remedy would involve hairshirts and moonlight. I'll post the results next year. Thanks again for your help. pooh

[freddy]

Hi pooh. You may want to consider using netting. I use Enviromesh which is VERY effective. Two drawbacks - one has to go to the trouble of putting up a framework to drape it over - and it's quite expensive. Mind you, it does last.
Cheers...freddy.