根腐菌(Phytophthora cinnamomi)是 Phytophthora属中最具毁灭性的种，会造成林业、园林与水果植物，以及大约 900种多年生木本植物的族群消减。(Ferraris et al.2004)
商业企业例如农业项目与相关的植物业，受到 P. cinnamomi真菌，不利的影响。例如，在意大利，它被越来越频繁地报导：首先发现在栗色灌木林与杜鹃属的植物上，发现在苗圃及最近发现在栗子和扁柏苗圃和鳄梨，橡木，胡桃木和高灌蓝莓。 P. cinnamomi会感染橡树，推测 P. cinnamomi在一般的地中海区域与橡树的严重衰微有关。(Robin et al. 2001). 病原体也在非洲大陆造成严重的损害，被认为是南非鳄梨果园最严重的疾病，造成根部腐烂，严重减少农作物生产量。(Bezuidenhout et al.1987)
P. cinnamomi对原生植物的影响间接影响野生动物。根据 Rudman(Undated)，到现在为止，澳洲塔斯梅尼亚181种植物，已经被记录为 P. cinnamomi的宿主。塔斯梅尼亚受威胁植物至少 39 种易受 P. cinnamomi感染，受传染区域的本土物种可能会快速死亡，无法再生。这种情况在其它地区有很大的差异，P. cinnamomi的不同宿主，有些显示出抵抗性，有些则非常脆弱。
P. cinnamomi有可能对北美原生生物群落造成重大生态破坏，从加州到阿巴拉契亚山脉。举例来说，一项 Ione 石兰科常绿灌木 ( Arctostaphylos myrtifolia) 枯死的科学研究发现， P. cinnamomi病原体是致死的元凶。病原体引起原生植物枯萎，树叶干枯与根部坏疽，一般相信它会严重影响已经濒危的 A. myrtifolia。(Swiecki 与 Bernhardt 2003). (Ione 石兰科常绿灌木是在内华达山脉的山麓小丘,加州中被局限于 Ione 形成土壤的一个稀有、透过皮肤发生作用、以及常绿的灌木。) 另一个情况在哪里 P. cinnamomi正在影响本地人加州的花似物种在 27% 的海岸生活橡树 (Quercus agrifolia) 的湖霍奇周围的森林地是显示疾病症状而且被猜想感染病原体 (Garbelotto 、 Huberli 与 Shaw 2006). 美国西部的所有自然橡木森林都可能因病原体而濒临生态损害的危险，Garbelotto, Huberli and Shaw (2006)的研究，有助于了解疾病因子(敏感度，其它害虫)，最终可能会有助于减少疾病的传播。美国其它地方的病原体也造成生态破坏。例如，北美东部的阿巴拉契亚森林，板栗森林在正在挣扎求生，这种情况部分归因于 P. cinnamomi的影响。虽然栗疫病历来与板栗枯死关系密切，板栗复原的主要障碍是Phytophthora属的卵菌病原体。最近在阿巴拉契亚森林种植的板栗幼苗死亡率很高，经由标准的诊断方法诊断出Phytophthora。(Rhoades et al.2003)
降低本地生物多样性: The following native plants are affected by Phytophthora cinnamomi: Epacris purpurascens var. purpurascens, Eucalyptus imlayensis, Genoplesium rhyoliticum, Leionema ralstonii, Tasmannia pupurascens, Westringia davidii and Wollemia nobilis. The southern brown bandicoot Isoodon obesulus and the smoky mouse (see Pseudomys fumeus in IUCN Red List of Threatened Species) are affected by the loss of habitat.
生态系统变化: Phytophthora cinnamomi causes severe disease in the understorey, or the shrub and ground layers of the vegetation in Tasmania. The susceptible species in Tasmania tend to come from the shrub and herbaceous families Dilleniaceae, Epacridaceae, Fabaceae, Proteaceae and Rutaceae. Resistant species generally belong to the grass and sedge families. The presence of P. cinnamomi can therefore lead to an understorey dominated by grasses or sedges.
经济 /民生: Root rot of avocado caused by P. cinnamomi is one of the most damaging diseases to South Africa's avocado orchards.
Sierra Nevada (United States (USA))
降低本地生物多样性: Ione manzanita (Arctostaphylos myrtifolia) is a rare, endemic, evergreen shrub restricted to Ione formation soils (infertile, acidic, sedimentary oxisols) in the foothills of the Sierra Nevada (near Ione). The widely distributed A. viscida (whiteleaf manzanita) intermixes with A. myrtifolia at the margins of Ione formation soils. Swiecki and Bernhardt (2003) examined mortality rates in this mixed vegetation and using scientific testing determined that wilting, foliage desiccation and root necrosis was being induced in the plants by the pathogenic fungus P. cinnamomi. This is the first report of root and crown rot caused by P. cinnamomi on A. myrtifolia and A. viscida. This disease will significantly impact conservation of the already threatened A. myrtifolia (Swiecki and Bernhardt 2003).
California (United States (USA))
病原: During an intense survey of natural woodlands around Lake Hodges (33°N, 117°W) in June 2001, symptoms typical of root and collar rot caused by Phytophthora spp. were observed on 27% of 474 coast live oaks (Quercus agrifolia) and on none of 86 Engelmann oaks (Q. engelmannii), in spite of intermixing of the two species. Symptoms on coast live oaks included viscous exudates emerging through intact bark matched by underbark dark lesions with irregular margins. Lesions were delineated by a dark line and present on the root collar or the buttress of symptomatic trees. Crowns of trees with lesions ranged from completely healthy to declining or dead. All symptomatic trees were in proximity of the lake or streams. P. cinnamomi was isolated and identified from trees in three distinct sites. Although Q. agrifolia is a known host for P. cinnamomi in California, this is the first report of widespread infestation of P. cinnamomi in natural oak woodlands in the western United States. Survey and inoculation results indicated Q. engelmannii to be less susceptible to infection. Inoculation results confirm previous research that cold temperatures are unfavorable to this pathogen and isolates differed in pathogenicity toward Q. agrifolia. Decline of oaks infected by P. cinnamomi was observed only in conjunction with other factors, in particular with the presence of the oak twig girdler, Agrilus angelicus Horn., an insect favored by stress conditions such as drought. Similar effects have been reported for Mediterranean oaks infected by the same pathogen (Garbelotto, Hüberli and Shaw 2006).
经济 /民生: Phytophthora cinnamomi is the cause of avocado root rot, the main limiting factor in avocado production. In California, it affects between 60 and 75% of orchards, and in 1989 caused an annual loss of approximately $44 million.