Phytophthora diseases likely to increase with climate change

Milder and wetter winters, followed by increased spring rainfall, are likely to enhance the survival and infection potential of many tree pathogens. Hotter, drier summers leading to drought stress in trees will also increase their susceptibility to disease and expand the distribution range of some pathogens. The increased incidence and severity of diseases caused by Phytophthora species reduces the benefits that trees provide, including climate change mitigation.

What are phytophthoras?

Phytophthoras are fungus-like pathogens that survive in their hosts overwinter or as dormant resting spores in soil and plant debris. Phytophthoras produce spores that swim in water films and are carried in water courses. Increased rainfall, waterlogged soil, flooding and water run-off increase their opportunities for infection and disease spread. Mycelia and spores can be transported in soil and plant debris. Some species, e.g. P. ramorum, produce spores that are adapted to aerial dispersal in mists and wind-driven rain.

About the series

Aimed at practitioners, the factsheets showcase the breadth of research carried out by Forest Research, sometimes over decades, into how trees and forests are facing the challenges of climate change, and actionable insights into how trees and woodlands can help mitigate the effects of climate change.