Detection of Airborne Plant Pathogens; Halting Epidemics Before they Start

• Published in: Outlooks on pest management Vol. 20; no. 1; pp. 11 - 14
• Main Authors: West, Jon S., Atkins, Simon D., Fitt, Bruce D.L.
• Format: Journal Article
• Language: English
• Published: Saffron Walden Research Information 01.02.2009; Research Information Ltd
• Subjects: Air Sampling; Diagnostics; Molecular Detection; Plant Pathogens; Spore Traps
• ISSN: 1743-1026; 1743-1034
• DOI: 10.1564/20feb05

History is full of examples of human, plant and animal diseases spread by airborne particles that have caused major social and economic impacts. Current concerns about the potential effect of the H5N1 influenza virus are partly founded on the influenza pandemic of 1918, which resulted in 20-50 million deaths. The 19th century Irish potato famine, which led to mass migration to the USA, was caused by an epidemic of potato late blight, initiated by airborne spores of Phytophthora infestans. The UK livestock foot and mouth epidemic in 2001 resulted in major economic damage to the rural community. Concerns about the use of airborne biological warfare agents remain an issue in the media. Early warning of disease risk by sampling the air and using new diagnostic methods to identify the pathogen inoculum rapidly can now greatly improve strategies for control of many of these epidemics. The focus of this article is on methods for detecting airborne inoculum of plant pathogens, in particular fungi. Airborne biological particles, or bioaerosols, include particles of biological origin or activity that can affect living organisms through infectivity, allergenicity or toxicity. Air dispersal is a major route by which many plant pathogens reach new territories; some fungal spores can travel thousands of kilometres, remaining viable and able to cause disease outbreaks that were not previously predicted. The impact of these diseases can be extensive, leading to severe crop losses, famine and mass migration. In 1961, the spread of wheat yellow rust in Washington and Oregon states of the USA led to yield losses valued at $45M. Phoma stem canker of oilseed rape, caused by Leptosphaeria maculans, causes losses worldwide of over $1000M and can result in 100 % yield loss in individual fields. Severe outbreaks in 1971 in Australia caused collapse of the rapeseed industry with plantings plummeting from 49,000 ha in 1972 to 2,000 ha in 1974. In 2007, farmers in the UK were hit by severe unpredicted epidemics caused by Sclerotinia sclerotiorum (sclerotinia stem rot of oilseed rape) and Puccinia triticina (brown rust of wheat).