Plant Pathology is not just for Christmas

Christmas dinners depend on control of plant diseases worldwide.

Spare a thought this Christmas for how plant diseases caused by pathogenic fungi, bacteria and viruses could affect your celebrations.

Why? Because the 12,000 tonnes or so of potatoes eaten have to be protected against the devastating potato blight, likewise Brussels sprouts from ring spot, light leaf spot and white blister, carrots from cavity spot. Even the stuffing is under threat with blight of chestnut trees. Less obvious accompaniments include the wine (grape mildew), beer (barley mildew), coffee (coffee rust), and if there is any room left after the meal, the chocolates are from cocoa bushes that survived or were protected from the well-named witches broom or black pod diseases.

Phytophthora infestans causing late blight of potato. Top left and bottom left: fairly healthy and 10 days later devastated potato field; right close up of blight lesions with fungal spores. Caused a social disaster in Ireland in 1840s and still one of the hardest diseases to control.

These "basics" are all taken for granted but are only there by controlling a whole range of diseases. Also our homes really wouldn't be complete at Christmas without the "trimmings" of 7.5 million conifer trees, potentially susceptible to Dothistroma needle blight; this would cause needles to drop even before you collected the tree! These comments apply of course to any meal, celebratory or not and is applicable worldwide. Many cultures are heavily dependent on rice for example, which succumbs to Magnaporthe rice blast, arguably of equivalent importance in those producing countries to potato blight. Our research makes sure that only high quality produce, free from diseases, makes it into your home and onto your plate.

2006 sees the British Society for Plant Pathology (BSPP) celebrating 25 years. 700 members from 50 countries around the world help lead the fight to control thousands of diseases, many of which have the capacity to devastate crops wherever they are grown. But the subject is much older than 25 years and diseases have frequently changed the course of history. The potato famine of 1845 resulted in the death of over 1 million people in Ireland, and America would certainly not have such an extensive Irish - American community without the mass exodus from Ireland during this period. Also Britain would probably not be a nation of tea drinkers if coffee rust had not wiped out the coffee bushes of Ceylon in 1869 leading to replacement by tea. More recently our landscape has been radically changed by Dutch elm disease and new diseases threaten oaks, alder and some conifers. However, most damage is still caused in developing countries where plant pathologists can help achieve the Millennium Development Goal to eradicate extreme hunger through improved food security. Major epidemics are still threatening the livelihoods and food supply of many communities with swollen shoot of cocoa in West Africa, cassava mosaic virus and coffee wilt in East Africa and banana bacterial wilt in Central Africa; all have major impacts on national economies and in turn the livelihoods of those in most need.

So plant pathologists not only protect your Christmas lunch but more importantly help the developing world to survive, by providing nutrition and to thrive through providing income. In developed countries pathologists strive to control disease with more environmentally friendly and sustainable methods, such as preventing accidental introductions, finding and using natural genes for resistance and employing benign microrganisms against those that cause disease. So....plant pathology is not just for Christmas! On December 19th at Imperial College London, many of these issues are to be discussed as part of a celebration of BSPP's anniversary, such as: the global impact of plant diseases, current and future disease threats, use of genes for resistance, the agrochemical perspective, alternative control measures, pathogens' arsenals and possible novel counter measures, public perception of plant diseases, the future of diseases and their control. Christmas dinners depend on control of plant diseases worldwide

Severe yield reduction of cassava caused by cassava mosaic virus in Uganda