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). A study in the Perth region found that dieback caused a significant shift in the bird community and affected nectar-feeding species the most, with fewer species such as the Western Spinebill in areas that were dieback-infested. Phytophthora 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, Phytophthora cinnamomi can also infect fruit trees, nut trees and other ornamental plants. Research has shown that Phytophthora 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 Phytophthora cinnamomi as an aggressive primary pathogen. The Invasive Species Specialist Group includes this species in its list of "100 of the World's Worst Invasive Alien Species". The potential range of this pathogen is expected to extend northward with warming of the climate. In gardens and crops Phytophthora dieback affects a large number of common garden species, natives and horticultural crops. This list of susceptible plants includes cinnamon, roses, azaleas and fruit trees. Since there is no known cure, once the disease has been introduced into a garden it cannot be easily eradicated, and can become a major problem. Protocols to prevent the disease from entering gardens include sourcing plants from non-dieback infested areas (not local bushland), using sterilised potting mixes, and using only mulch that has been properly composted. Transplanting established plants from one garden to another can also spread the disease. Propagating from seed and cuttings is less likely to transmit the disease because there is no soil transported with stock. Many nurseries are accredited under the Nursery Industry Accreditation Scheme Australia (NIASA) and use hygienic practices to prevent Phytophthora dieback from infecting their stock. Hygienic practices prevent the spread of