Onion neck rot

What you see

Nothing at all at harvest - then, weeks into storage, the neck of the bulb softens, sinks and greys with a dense felt of mould, and the whole onion collapses from the top down. Small black crusts form between the scales.

Conditions

Infection happens in the field, usually in a wet late season, but only shows in store. Warm, humid, poorly ventilated storage completes the job.

Treatment

Sort the store weekly and remove every soft bulb. Nothing can be treated - the aim is to stop one bulb infecting the sack.

Prevention

Stop watering onions once the tops begin to fall. Cure them properly: two to three weeks somewhere dry and airy until the necks are papery and rustle. Store cool, dry and hanging in nets, never in a sealed box.

Months: July, August, September, October, November, December

Plants

Onion, Shallot, Garlic

Remedies

Not recorded — the field is blank rather than guessed.

The thing people get wrong

The whole disease is decided by curing, and curing is the step everyone shortens. An onion whose neck is still slightly soft and green when it goes into the net is an onion that will rot in November. Bend the tops over, lift on a dry day, and leave them until the neck rustles between your fingers - that sound is the actual test.