Table 2 Examples of the ecological, economic, social and scientific impacts of selected Phytophthora species
Phytophthora speciesa | Clade | First described | Environments | Main diseases caused and impacts | Scopus indexed articles and their citations |
|---|---|---|---|---|---|
P. agathidicida | 5 | 2015 | Forest, park | Dieback of Kauri, one of the world’s largest and longest-living conifer species, in New Zealand, spreading since 1974. Negative impact on both forest ecosystems and Mauri society due to the ecological and cultural significance of Kauri trees | 29/171 |
P. austrocedri (syn. P. austrocedrae) | 8 | 2005 | Forest, natural ecosystem | Dieback and mortality of native Austrocedrus forests in the southern Andes. Dieback and mortality of native Juniper, UK, initially associated with restoration planting of infested nursery stock | 26/135b |
P. cactorum | 1 | 1886 | Agriculture, forest, nursery | Root, collar, crown and fruit rots and stem cankers on over 200 species of trees, ornamentals, and fruit crops in 160 genera worldwide | 586/6481 |
P. capsici | 2 | 1922 | Horticulture | Phytophthora blight of Capsicum in the Americas and Southeast Asia, and a major limiting factor to vegetable production globally, especially cucurbits, tomatoes, and succulent beans, causing up to 100% losses in individual fields | 1559/18,150 |
P. cinnamomi | 7 | 1922 | Forest, heathland, nursery, garden | Dieback of eucalypt forests and woodlands and mass destruction of World Heritage heath flora in Western Australia since 1950s. Heavy mortality of Fagaceae in forests of southeastern US since 1940s and southern Europe since ~ 1990s. Damage to ornamental nursery trade in Europe since 1970s. Listed as one of the 100 worst invasive alien species; pathogenic to ~ 5000 trees, woody ornamentals, and herbaceous plants worldwide | 1331/12,976 |
P. cryptogea | 8 | 1919 | Horticulture, nursery, garden | Root and collar rot on a wide range of crops, fruit trees and ornamentals worldwide. Particularly important pathogen in greenhouses | 272/5261 |
P. fragariae | 7 | 1940 | Horticulture | Red core root disease of strawberry since 1920s, causing serious economic losses in strawberry plantations across humid regions of Europe and North America, with severely reduced yields and small poor-quality fruit. In Canada production losses to growers of Can$ 1500 per ha | 178/2091 |
P. infestans | 1 | 1876 | Agriculture, horticulture | Late blight of potato and tomato, notorious for the Irish potato famine 1845–1849 resulting in mass starvation and migration. Currently still a serious threat to global food security worldwide, with US$ 6.7 million annually in yield losses and control costs | 4241/44,346 |
P. kernoviae | 10 | 2005 | Forest, heathland, horticulture, park | Aerial bleeding cankers on European beech and leaf and shoot blights of Rhododendron, Magnolia spp., and wild bilberry in the UK and Ireland | 59/976 |
P. lateralis | 8 | 1942 | Forest, nursery, park, shelterbelt | Root disease causing heavy mortality of Port Orford cedar (Chamaecyparis lawsoniana) in its native range in Oregon and California since 1950s. Serious impact on trade in this valuable commercially harvested timber. Recently spread to ornamental C. lawsoniana in western Europe. Social impacts through loss of business in nursery and forestry sectors | 62/1471 |
P. megakarya | 4 | 1979 | Agroforestry | Main cause of Black pod disease of cocoa trees in central west Africa since the early 1900s, recently spread to Ghana. Loss of yield often > 30% for the economically important cocoa industry, worth ca US$ 70 billion annually | 106/2301 |
P. nicotianae (syn. P. parasitica) | 1 | 1896 | Agriculture, horticulture, nursery, garden | Severe diseases of agricultural and horticultural crops worldwide, including foot rot and gummosis of citrus, black shank of tobacco and collar rot of tomato. Also on ornamentals. Broad host range, infects > 255 genera in 90 plant families | 1235/17,464b |
P. palmivora | 4 | 1919 | Agroforestry, nursery, garden | Major impact on the production of tropical tree crops including black stripe disease of rubber in Southeast Asia since early 1900s. Also Black pod disease of cocoa in Southeast Asia and the Caribbean, with annual global losses to the cocoa industry of ca 450,000 t valued at > US$ 1 billion. Many ornamental hosts | 567/5892 |
P. plurivora | 2 | 2009 | Forest, nursery, park, garden | Root and collar rot and aerial stem cankers on a wide range of woody hosts in Europe and North America; involved in the decline of oak and beech across Europe. Severe impact on the ornamental nursery industry | 66/644 |
P. quercina | 12 | 1999 | Forest, park | Host-specific fine root pathogen. A main driver of the chronic decline of oak forests across Europe, interacting with climatic extremes | 53/896 |
P. ramorum | 8 | 2001 | Forest, nursery, garden | Over 200 plant hosts. High impact. Cause of Sudden oak death (native tanoak and other species) in the Western US since ~ 2000. Through loss of tanoak seed production, a significant impact on local wildlife and native American culture. Cause of Sudden larch death in the UK and Ireland since ~ 2010 with ~ 200 km2 plantation larch affected and millions felled Currently a threat to commercial timber production in the US (> US$ 30 billion) and the UK. Also damaging to the ornamental nursery trade in Europe and North America e.g. the rhododendron export trade in Canada (around US$ 5 million) | 627/8560 |
P. rubi (syn. P. fragariae var. rubi) | 7 | 2007 | Horticulture | Extremely serious disease of raspberry plantations in Europe, North America, and elsewhere. EPPO A2 list, recommended for phytosanitary treatments | 57/475b |
P. sojae (syn. P. megasperma var. sojae) | 7 | 1958 | Horticulture | Devastating root and stem rot of soybean in the US, with an annual cost worldwide of US$ 1–2 billion | 810/13,592b |
P. syringae | 8 | 1909 | Horticulture, nursery, garden | Root and collar rot, stem cankers, leaf and shoot blights and fruit rot on a medium-wide range of host plants including fruit trees and lilac | 71/2207 |
P. ×alni | 7 | 2004 | Riparian forest, nursery | Extensive mortality of riparian alder across Europe since 1990s, driven by planting of infested nursery stock. Impacts ecosystem functions and services and riverbank stability. EPPO alert list 1996 to 2001 | 72/772 |
P. ×cambivora | 7 | 1927 | Forest, horticulture, nursery, garden | Root and collar infections (Ink disease) of sweet chestnut and beech in Europe. Root rot of various fruit trees in Europe and the US since 1900s. Significant impact on ornamental nurseries | 142/2259 |