Killer pathogens have been all over the news - here's your chance to get your students hands-on in the role of plant pathologists.

In this new practical, students track down leaf pathogens under the microscope, as a starting point to consider the global impact of disease on society and the environment.

The topic would make a contemporary science club activity, but is relevant to many aspects of A-level biology, such as leaf structure during the teaching of photosynthesis, productivity of crop species and reasons for using pest control.

Some diseases (e.g. black spot on some herbaceous plants) will change the colour of infected plant cells dramatically (e.g. from dull green to a bright pink), allowing cells, stomata, guard cells and trichomes to be much more clearly seen. This may therefore make an interesting alternative practical when looking at specialised cells under the microscope.

This practical was developed by teacher and SAPS Associate Sarah Bayliss, after attending the Gatsby Plant Science Summer School 2011.

Photo shows a tea plantation under attack from Pantoea agglomerans, a bacterium that attacks both plants and immuno-compromised humans. Photo by Dr Abhaya Balasuriya,from the British Society for Plant Pathology image gallery.