Professors' Bruce Fitt research protects vital crops
Given the fragile state of the world’s economy, and growing concerns over food shortages and climate change, protecting arable crops from disease is more vital than ever. Work being done by Professor Bruce Fitt at the University of Hertfordshire, examining the global spread of phoma stem canker in oilseed rape crops, is proving to be a valuable step forward in managing this particularly serious threat.
Oilseed rape is one of the world’s most important brassica crops. Grown for the production of vegetable oil, and for use in bio diesel and animal feed, oilseed rape makes a significant contribution to the agricultural economies of Europe, Australia, Canada, China and India.
Worldwide production of oilseed is increasing. The United Nations Food and Agriculture Organisation (FAO) estimates that over fifty-eight million tonnes were produced in the 2010-2011 cropping season, compared with thirty-six million tonnes in the 2003-2004 season. At the current price of £400 per tonne, widespread crop losses from disease have serious economic consequences.
‘Oilseed rape and other brassicas are prone to phoma stem canker, also known as blackleg disease, caused by the virulent pathogen Leptosphaeria maculans. This has been spreading globally over the last thirty years, particularly across Canada and into countries previously colonised by the less damaging pathogen Leptosphaeria biglobosa. Worldwide, phoma stem canker is currently responsible for losses worth more than £1200 m per season,’ explains Bruce Fitt, Professor of Plant Pathology at our School of Life Sciences.
Professor Fitt is a leading authority on oilseed rape diseases, and he has spoken about this particular work at recent international conferences in Canada and Prague. In the UK, his group’s web-based forecasts about the diseases have been widely used by industry since the mid-1990s.
A number of factors point to China – the world’s biggest producer of rapeseed – being at risk. The less damaging pathogen Leptosphaeria biglobosa is already present in some areas of the country. Chinese cultivars of winter oilseed rape are particularly susceptible to Leptosphaeria maculans. Also, China imports several million tonnes of oilseeds each year, and seed contamination is a route the disease spreads between countries.
‘To establish a realistic picture of the possible threat to Chinese crops, we produced a computer model plotting the spread of Leptosphaeria maculans across Canada over a fifteen-year period from the mid-1980s to the late 1990s. We then applied it to China, across the main oilseed rape growing provinces along the Yangtze river basin, assuming entry via the port of Shanghai,’ says Professor Fitt.
The study assesses both the potential risk and predicted economic losses of Leptosphaeria maculans being introduced to China. A number of the recommendations about preventing severe epidemics of phoma stem canker have already been taken up by China. Short-term strategies include training farmers and extension workers to recognise the symptoms of the disease, to use special diagnostics methods developed by Professor Fitt’s team to detect Leptosphaeria maculans on imported seed, and importing rapeseed oil rather than importing the seed and crushing this locally. Long-term strategies focus on introducing genes to the Chinese cultivars to build disease resistance.