When I lifted my onions yesterday I found some of them had a white furry stuff round the bottom of onion .Are they still edible and also what is it..If a fungal desease do I need to treat the ground where they were planted before I sow there again
Sounds like Onion White Rot ... info here https://www.rhs.org.uk/advice/profile?pid=480
Hope that helps.
I am afraid Dove is right- White rot is very persistant, there is no treatment for the ground except to have a bonfire on it, & that is only partially effective. You may be able to use the onions but they will not store well. Try not to sow there again for as long as you can they used to say 5 years then it went to 7 now its even more. Some say you can trick the fungus by watering with garlic solution 3-4 weeks before you want to sow/ plant this makes the dormant spore germinate and then with nothing to feed on they die. I have not tried it myself. If you grow the onions in a pot or even better a root trainer module you get a strong root system & plant the whole plug with fresh bagged compost in the hole this can help a bit as well.
Thank you both for your help,, I much appreciate it,