onion fly

[janebb]

Everyone on our allotment had a real problem with onion fly this year.  One minute my leeks were looking lovely and the next they were a heap of wriggling mush. Do you think it is safe to grow onions and leeks next season or do you think I should have a break from them?  I pulled up my leeks as soon as I realised that there was a problem but I am not sure that everyone on the allotment did. I am worried that some of the pupa will have turned into onion flies and laid eggs in the soil. Can onion fly eggs survive a winter in the soil?

[janebb]