Mangold Leaf Miner on Beetroot

[Monika]

My husband has got this pest on his beetroot which he also had last year and a very poor crop of beetroot as a result.

He has read that you have to take off the affected leaves and spray with Malathion, but this is one of the withdrawn chemicals and no others are mentioned.

Any tips please?

[Monika]

[Jayb]

I've not had this problem but found some info on the Guardian's site from Alys Fowler. Doesn't mention spraying but looks like picking off affected leaves and squishing is the way to go. Might be worthwhile fleecing if he sows another batch on clean ground.

http://www.guardian.co.uk/global/2010/jun/12/alys-fowler-biennial-seed-beet-leaf-miner "The fly is an inconspicuous little thing, merely 6mm long, and emerges in May after overwintering as a pupa in the soil. It lays its eggs on the underside of the leaf. The larvae hatch after about a week, tunnel in between the two surfaces of the leaf and munch the tender stuff in between. After about three weeks of feeding, they drop off into the soil to pupate. This life cycle happens two or three times over the summer. The beet fly attacks perpetual spinach, Swiss chard, fat hen, orache and beetroot. It's not so much of a problem in beetroot, because you don't tend to eat the leaves and it doesn't have much effect on the overall health of the plant.

Pick off infected leaves and squish any larvae before putting the leaves on the compost. If the problem gets really bad, the best method is prevention: cover crops with fine mesh netting or fleece, so the flies can't lay eggs. Deep cultivation in the winter can help to keep down numbers, too."

[Monika]

Thanks very much Jayb - I have passed the information on