Field trials and validation experiments are currently underway in the Institute of Biological Sciences (IBS) at the University of Wales, Aberystwyth to test an automated system that can identify and count airborne potato blight spores.
The system, which has been developed by Dr Gareth Griffith and colleagues in IBS, involves the connection of the flow cytometer to a high volume (600 l/min) air sampler.
This is said to increase the volume of air sampled during a given period, resulting in greater sensitivity, and introduces a degree of automation to the process of identifying the particles, which is currently done manually.
‘Evolutionary algorithms’, notably Genetic Programming are used to devise simple rules which provide accurate particle identification with very low levels (<2%) of false positive and false negative readings.
Flow cytometry is used to count and identify blight sporangia against a background of other fungal spores, pollen and inert particulates that are present in the air.
Particles collected by the sampler are trapped in a small volume of stain solution and analysed using a flow cytometer equipped with three lasers.
Transfer of sample and data analysis are conducted automatically, allowing the device to run unmanned for periods of several days.
‘Climatic forecasting can inform as to whether conditions are suitable for pathogen spread but this will only occur if inoculum (sporangia) of the pathogen are present in the air spora,’ said Dr Griffith.
‘Hence the ability to detect low number of spores in the air during the early part of the growing season will greatly enhance our ability to forecast the disease. Successful validation of this new approach will mean that potato growers could avoid the unnecessary spraying of fungicides early in the growing season’.
Since many living organisms rely on air currents for the dispersal of their pollen or spores, this technology could also have important medical applications by advancing the understanding of the patterns of release and dispersal of allergenic plant pollen, and also of allergenic and plant pathogenic fungal spores.