Science Into Practice - Rot diseases in onion sets

There is a perception that the risk of certain onion diseases may be increased when crops are grown from sets.

Of major concern are bacterial rots thought to be caused mainly by Burkholderia gladioli pv. alliicola (BGA) - particularly in heat-treated red Rijnsburger-type onions, neck rot caused primarily by Botrytis allii and Fusarium basal rot caused by Fusarium oxysporum fsp cepae.

One possibility is that necessary heat treatment of some cultivars may lead to increased disease risk. Project FV 392 was a first step to address these issues by determining the incidence of the major bacterial and fungal onion pathogens thought to be associated with sets of different types and establish whether there is a relationship between disease incidence in sets and subsequent problems in the harvested bulb onion crop.

The results showed that the main cause of rots in stored onion bulbs grown from sets was the bacteria BGA and the fungus Fusarium oxysporum. The neck rot pathogen, Botrytis aclada, was not detected.

There was an indication that the primary source of BGA may be sets and that heat treatment may predispose them to or exacerbate infection/disease in the harvested bulbs. Bulk testing of sets for BGA may give an indication of the risk of disease in the harvested crop.

The primary source of Fusarium in these trials appeared to be the field sites themselves, with a different Fusarium "type" responsible for disease at each site.

The final grower summary for FV 392 is available on the HDC website at

Horticultural Development Company

For details on all HDC activity, visit

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

Is a post-Brexit seasonal worker scheme now impossible?

Is a post-Brexit seasonal worker scheme now impossible?

The UK fresh-produce sector has reacted with dismay at the latest developments in the ongoing debate, largely conducted out of public view, on whether UK horticulture will still have access to seasonal migrant workers when the UK leaves the EU in 18 months' time.

Can UK fresh produce come out of Brexit ahead?

Can UK fresh produce come out of Brexit ahead?

UK production horticulture can become more profitable under one possible Brexit scenario, while other more drastic scenarios will lead to only minor losses in profitability, a new report argues.

Business Planning - Staff are your greatest asset

Business Planning - Staff are your greatest asset

An effective strategy to retain staff is the best way for any business to avoid a potential recruitment crisis, Neville Stein advises.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Professor Geoffrey Dixon

GreenGene International chair Geoff Dixon on the business of fresh produce production

Read Professor Geoffrey Dixon