The fungus Sclerotinia sclerotiorum is an important plant pathogen causing Sclerotinia disease on many plant species. Important agricultural and horticultural crops such as oilseed rape, lettuce, carrot, vegetable brassicas, peas, beans and potatoes are all affected as well as wild plant hosts such as broad leaved weeds and wild flowers. The pathogen survives in soil as sclerotia (resting structures) 1-10 mm in diameter and when conditions are favourable, they germinate to produce small mushroom-like apothecia which eject ascospores into the air. These spores then infect plants causing rotting and plant death. The overall aim of our research is to understand the epidemiology, population structure and biology of the pathogen with the aim of improving disease management strategies.

Sclerotinia research

• Understanding the population structure, diversity and biology of S. sclerotiorum isolates from wild and crop hosts
• Understanding the environmental conditions that affect key stages in the pathogen lifecycle and developing disease forecasting strategies through 1) predicting the production of apothecia/ascospores by germinating sclerotia and 2) identifying conditions for ascospore germination and infection
• Identification of resistance in lettuce, brassica and carrot
• Control of S. sclerotiorum using biofumigation

Research Projects

• PhD: Understanding the impacts of temperature and soil moisture on the germination of Sclerotinia sclerotiorum sclerotia (2014-2017)Link opens in a new window

• PhD: AHDB CP 80: Pathogen diversity, epidemiology and control of Sclerotinia disease in vegetable crops (2011-2014)Link opens in a new window

• Defra IF0188: Plant pathogen populations in wild and agricultural hosts and interactions with plant genotype (2009-2013)Link opens in a new window
• LINK LK09130 PR 538: Reducing the impact of sclerotinia disease on arable rotations, vegetable crops and land use (2009-2013)Link opens in a new window
• Defra HH3230SFV: Factors affecting the inoculum potential of soilborne plant pathogens (2005-2009)Link opens in a new window
• AHDB FV 294: Outdoor lettuce: forecasting and control of Sclerotinia (2006-2008)
• Defra HH3215TFV: Forecasting Sclerotinia disease in field grown lettuce (2003-2005)Link opens in a new window

Selected publications

• Taylor A, Coventry E, Handy C, West JS, Young CS, Clarkson JP, 2018. Inoculum potential of Sclerotinia sclerotiorum sclerotia depends on isolate and host plant. Plant Pathology 67, 1286-1295.
• Navaud O, Barbacci A, Taylor A, Clarkson JP, Raffaele S, 2018. Shifts in diversification rates and host jump frequencies shaped the diversity of host range among Sclerotiniaceae fungal plant pathogens. Molecular Ecology 27, 1309-1323.
• Taylor A, Rana K, Handy C, Clarkson JP, 2017. Resistance to Sclerotinia sclerotiorum in wild brassica species and the importance of Sclerotinia subarctica as a brassica pathogen. Plant Pathology 67, 433-444.
• Clarkson JP, Warmington RJ, Walley PG, Denton-Giles M, Barbetti MJ, Brodal G, Nordskog B, 2017. Population structure of Sclerotinia subarctica and Sclerotinia sclerotiorum in England, Scotland and Norway.
• Brodal, G, Warmington R, Grieu C, Ficke A, Clarkson JP, 2016. First report of Sclerotinia subarctica nom. prov. (Sclerotinia sp. 1) causing stem rot on turnip rape (Brassica rapa subsp. oleifera) in Norway. Plant Disease 101, 306.
• Warmington R, Clarkson JP, 2015 Volatiles from biofumigant plants have a direct effect on carpogenic germination of sclerotia and mycelial growth of Sclerotinia sclerotiorum. Plant and Soil 401, 213–229.
• Clarkson JP, Fawcett L, Anthony SG, Young C (2014) A model for Sclerotinia sclerotiorum infection and disease development in lettuce, based on the effects of temperature, relative humidity and ascospore density. PLoS ONE 9, e94049.
• Clarkson JP, Coventry E, Kitchen J, Whipps JM (2013) Population structure of Sclerotinia sclerotiorum in crop and wild hosts in the UK. Plant Pathology 62, 309–324.
• Clarkson JP, Carter HE and Coventry E (2010) First report of Sclerotinia subarctica nom. prov. (Sclerotinia species 1) in the UK on Ranunculus acris. Plant Pathology 59, 1173.
• Clarkson JP, Clewes E, Whipps JM, 2008. Diversity of Sclerotinia sclerotiorum from agricultural crops and meadow buttercup in the UK. Journal of Plant Pathology 90, S2.
• Clarkson JP, Phelps K, Whipps JA, Young CS, Smith JA, Watling M, 2007. Forecasting Sclerotinia disease on lettuce: A predictive model for carpogenic germination of Sclerotinia sclerotiorum sclerotia. Phytopathology 97, 621-631.
• Clarkson JP, Phelps K, Whipps JM, Young CS, Smith JA, Watling M, 2004. Forecasting Sclerotinia disease on lettuce: Toward developing a prediction model for carpogenic germination of sclerotia. Phytopathology 94, 268-279.
• Young CS, Clarkson JP, Smith JA, Watling M, Phelps K, Whipps JM, 2004. Environmental conditions influencing Sclerotinia sclerotiorum infection and disease development in lettuce. Plant Pathology 53, 387-397.
• Jones EE, Clarkson JP, Mead A, Whipps JM, 2004. Effect of inoculum type and timing of application of Coniothyrium minitans on Sclerotinia sclerotiorum: influence on apothecial production. Plant Pathology 53, 621-628.
• Clarkson JP, Staveley J, Phelps K, Young CS, Whipps JM, 2003. Ascospore release and survival in Sclerotinia sclerotiorum. Mycological Research 107, 213-222.
• Clarkson JP, Whipps JM, 2002. Control of sclerotial pathogens in horticulture. Pesticide Outlook 13, 97-101.

Further information

Please contact john.clarkson@warwick.ac.uk