Onion (Allium cepa) is an important horticultural crop which is cultivated by every agricultural nation in the world with an annual production of 78.5M tonnes and a value of £9,500M. It is the second most valuable vegetable crop in the world behind the tomato and in the UK, production is valued at approx. £110M per year. Onions are a staple crop and deliver a range of health benefits including anticarcinogenic, antithrombotic and antibiotic effects.

Fusarium basal rot (FBR) caused by Fusarium oxysporum fsp. cepae (FOC) and Allium white rot (AWR) caused by the fungus Sclerotium cepivorum and are two major soilborne diseases of onions and other Allium crops. Both diseases are very difficult to control as they form long-lived survival structures which remain in the soil for many years; chlamydospores for F. oxysporum and sclerotia for S. cepivorum. FOC infects roots directly through germination of spores in the soil and predominantly causes a bulb rot on onions later in the season or more often in store. However, the pathogen can also cause symptoms at any stage of plant development. It is an increasing problem for onion growers in the UK and globally it is predicted to worsen under current climate change models. S. cepivorum sclerotia germinate and infect roots through hyphae in response to specific chemical compounds released from onion roots. This results in wilting and subsequent plant death during the growing season with more sclerotia being produced and returned to the soil.

The overall aim of our research is to characterise these and other onion pathogens using molecular methods, understand their biology and develop alternative and more sustainable ways of reducing their impact for onion growers.

A recently awarded BBSRC HAPI project in collaboration with Richard Harrison at East Malling Research and industry partners Hazera Seeds and AHDB Horticulture is investigating both the genetic basis for pathogenicity in FOC and for new sources of resistance in onion. An accompanying PhD project being carried out by Sascha Jenkins is investigating the pathogenicity of Fusarium spp. on pea.

Fusarium Basal Rot Research
Allium White Rot Research

Research Projects


Selected Publications