Plant disease epidemiology

Last changed: 14 April 2021

Plant disease epidemiology studies the spatial and temporal dynamics as well as the ecology of the interaction between populations of plant pathogens, plant hosts, and the environment.

A better understanding of these interactions will lead to environmentally friendly and sustainable crop production systems, which are the key to food production. Understanding these interactions is the first step to adherence to the EU 'Sustainable Use' directive (often called the IPM directive).

We study pathogen populations and their interactions

We use modern, state-of-the-art methods to study pathogen populations and their interactions. Modern molecular tools that use markers based on the pathogen DNA have enabled studying them at a resolution that was not possible using older phenotying markers, such as morphoology or virulence to specific resistance genes. 

We have focused on some of the main staple food crops grown in Sweden, such as potatoes and small grains, because these crops are a basic component of the food supply, but also because diseases in these crops are responsible for a large amount of pesticide use in Sweden. As a result, we are one of the leading European groups studying late blight of potato, as well as some of the rusts and leaf blights on small grains.

Anna Berlin analyze material from spore traps in order to develop early detection of plant diseases. Photo: Cajsa Lithell.
Potatos are often infected with Phytophthora infestans, an oomycete that causes the serious potato disease known as late blight or potato blight. Photo: Cajsa Lithell.
The stem, black and cereal rusts are caused by the fungus Puccinia graminis and are a significant disease affecting cereal crops. Crop species which are affected by the disease include bread wheat, durum wheat, barley and triticale. Photo: Joanthan Yuen.

The population biology and structure of several pathogens are targeted, including:

  • Phythophthora infestans on potato and tomato
  • Alternaria in potato
  • Several Puccinia species on small grains
  • Several leaf spot and head blight pathogens on small grains
  • Ralstonia and Xanthomonas in a tropical context

Some of the population interactions we study are:

  • Resistance to fungicides
  • How host plant resistance affects pathogen populations
  • Effects of climate change on plant diseases
  • Landscape level processes that affect plant disease development


Jiasui Zhan, Professor

Department of Forest Mycology and Plant Pathology, Division of Plant Pathology/Epidemiology, 018-672369
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