Innovations in air sampling to detect plant pathogens.

Js West,Rbe Kimber

doi:10.1111/aab.12191

Abstract

Many innovations in the development and use of air sampling devices have occurred in plant pathology since the first description of the Hirst spore trap. These include improvements in capture efficiency at relatively high air-volume collection rates, methods to enhance the ease of sample processing with downstream diagnostic methods and even full automation of sampling, diagnosis and wireless reporting of results. Other innovations have been to mount air samplers on mobile platforms such as UAVs and ground vehicles to allow sampling at different altitudes and locations in a short space of time to identify potential sources and population structure. Geographical Information Systems and the application to a network of samplers can allow a greater prediction of airborne inoculum and dispersal dynamics. This field of technology is now developing quickly as novel diagnostic methods allow increasingly rapid and accurate quantifications of airborne species and genetic traits. Sampling and interpretation of results, particularly action-thresholds, is improved by understanding components of air dispersal and dilution processes and can add greater precision in the application of crop protection products as part of integrated pest and disease management decisions. The applications of air samplers are likely to increase, with much greater adoption by growers or industry support workers to aid in crop protection decisions. The same devices are likely to improve information available for detection of allergens causing hay fever and asthma or provide valuable metadata for regional plant disease dynamics.

Highlights

Dispersal in air is one of many mechanisms by which plant pathogens can spread to reach new susceptible plants either within the same field or even in a completely different continent (Pady & Kapica, 1955; Gregory, 1973; Brown & Hovmøller, 2002). Gregory (1973) predicted that most spores of plant pathogens do not disperse beyond the field in which they were produced
The simplicity of its design has been a key reason for this – comprising just three moving parts: electric motor, bearing to turn the air intake into the wind, and a clockwork mechanism to move the collection surface past the air intake. It has been used in hundreds of studies of airborne pollen and plant- or fungal-spores, in modified forms such as the Burkard seven-day spore trap, which replaces collection onto a glass slide by collection of particles onto adhesive tape on a circular drum that rotates over a period of seven days
For collection of very small particles, below 1 μm aerodynamic diameter, wet cyclones or liquid impingers are the best samplers to use – the Coriolis Air Samplers can operate at 100–600 L min−1 for up to 6 h if circulating fluid is replenished periodically

Summary

Introduction

Dispersal in air is one of many mechanisms by which plant pathogens can spread to reach new susceptible plants either within the same field or even in a completely different continent (Pady & Kapica, 1955; Gregory, 1973; Brown & Hovmøller, 2002). Gregory (1973) predicted that most spores of plant pathogens do not disperse beyond the field in which they were produced. For collection of very small particles, below 1 μm aerodynamic diameter, wet cyclones or liquid impingers are the best samplers to use – the Coriolis Air Samplers can operate at 100–600 L min−1 for up to 6 h if circulating fluid is replenished periodically.

Results

Conclusion