Phytophthora Cinnamomi - Phytophthora Cinnamomi in The Wild

Phytophthora Cinnamomi in The Wild

When Phytophthora dieback spreads to native plant communities, it kills many susceptible plants, resulting in a permanent decline in the biodiversity and a disruption of ecosystem processes. It can also change the composition of the forest or native plant community by increasing the number of resistant plants and reducing the number of susceptible plant species. Native animals that rely on susceptible plants for survival are reduced in numbers or are eliminated from sites infested by Phytophthora dieback.

Damage to forests suspected to be caused by P. cinnamomi was first recorded in the United States about 200 years ago. Infection is the cause of sudden death of a number of native tree species, including American Chestnut, Littleleaf disease of Shortleaf Pine (Pinus echinata), Christmas tree disease in nursery grown Fraser Fir (Abies fraseri), while oaks are affected from South Carolina to Texas.

In Australia, where it is known as Phytophthora dieback, dieback, jarrah dieback, or Cinnamon fungus P. cinnamomi infects a number of native plants, causing damage to forests and removing habitats for small mammals.

Of particular concern is the infection and dieback of large areas of forest and heathland which support threatened species in the south-west corner of Western Australia. Many plants from the genera Banksia, Darwinia, Grevillea, Leucopogon, Verticordia and Xanthorrhoea are susceptible. This in turn will impact on animals reliant on these plants for food and shelter, such as the Southwestern Pygmy Possum (Cercartetus concinnus) and the Honey Possum (Tarsipes rostratus).

P. cinnamomi is also a problem in the Mexican state of Colima, killing several native oak species and other susceptible vegetation in the surrounding woodlands. It is implicated in the die-off of the rare endemic shrub Ione manzanita (Arctostaphylos myrtifolia) in California, as well.

In addition to damage to native woodlands, P. cinnamomi can also infect fruit trees, nut trees and other ornamental plants. Research has shown that P. cinnamomi can infect club mosses, ferns, cycads, conifers, cord rushes, grasses, lilies and a large number of species from many dicotyledonous families. This is a remarkable range for a plant pathogen and highlights the effectiveness of P. cinnamomi as an aggressive primary pathogen. This species has been named among the 100 of the "World's Worst" invaders.