New data on Phakopsora rusts of grapevine and soybean
Phakopsora rusts are serious diseases of major crops such as cotton, soybean and grapevine in the tropics. Recently, new data has been made available on grapevine and soybean Phakopsora rusts:
1) the taxonomy of the fungus involved in grapevine and other vitaceous hosts has been clarified;
2) soybean rust is currently spreading in African countries.
Grapevine rust
The taxonomy of Phakopsora rusts occurring on grapevine and other vitaceous hosts in Asia has been clarified by Ono (2000), and three distinct species are now proposed:
- P. ampelopsidis which is restricted to Ampelopsis, Cayratia and Cissus. This fungus occurs in Asia (China, Japan, Korea and Philippines)
- P. vitis which is restricted to Parthenocissus tricuspidata. It occurs in Asia (China, Japan, Korea, Nepal).
- P. euvitis which is restricted to Vitis (mainly V. labrusca, V. vinifera, but also V. amurensis, V. coignetiae, V. ficifolia, V. flexuosa). P. euvitis is a heteroecious rust. Pycnidia and aecia have only been observed in Japan on Meliosma myriantha (in the small family Sabiaceae). In most other areas, only uredia and telia are produced on grapevine. P. euvitis occurs in Asia (Bangladesh, China, India, Indonesia, Japan, Korea, Democratic People’s Republic of Korea, Myanmar, Philippines, Sri Lanka, Thailand). There are many records of grapevine leaf rust in the Americas (Colombia, Guatemala, Honduras, Jamaica, Mexico, USA). However, the distribution of P. euvitis needs further work, as in particular another species P. uva has been described from diseased grapevines in Colombia and Mexico. There is also one record from the Russian Far East. Finally, P. euvitis has been reported in 2001 in Australia, in the Darwin area which is not a major grapevine-growing area. It is thought that the disease came via air-borne spores from South East Asia.
Soybean rust
Two distinct Phakopsora species are involved in soybean rust: P. pachyrhizi which occurs in Asia and Oceania, and P. meibomiae which occurs in the Americas. Infected soybean plants show foliar lesions, premature defoliation and yield reduction. In recent years, reports on outbreaks of soybean rust in several African countries have been made. In 1998, soybean rust was reported in Rwanda and Uganda, in 1999 in Mozambique, Nigeria and Zambia. In 2000 and 2001, P. pachyrhizi was identified in Nigeria (Oniyo region Oyo state) and in South Africa (KwaZulu-Natal). P. pachyrhizi also occurs in Ghana, Sierra Leone, and Tanzania.
Note: The Phakopsora pathogens on soybean are tropical, requiring in particular long periods of high humidity for their development. They therefore do not present any particular risk to the EPPO region. Concerning Phakopsora euvitis, although it is reported to be more severe in tropical and subtropical regions than in temperate areas, the EPPO Secretariat felt that P. euvitis could be added to the EPPO Alert List to draw countries’ attention to this potentially dangerous pathogen.
Sources
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CABI draft datasheets on Phakopsora ampelopsidis, P. euvitis, P. meibomiae, P. pachyrhizi, P. vitis.
Leu, L.S. (1988) Rust. In: Compendium of grapevine diseases (ed. by Pearson, C.R.; Goheen, A.C.) pp 28-30. APS, St Paul, Minnesota, USA.
Ono, Y. (2000) Taxonomy of the Phakopsora ampelopsidis species complex on vitaceous hosts in Asia including a new species, P. euvitis.
Mycologia, 92(1), 154-173 (abst.).
Sinclair, J.B.; Hartman, G.L. (1999) Soybean rust. In: Compendium of soybean diseases. 4th edition (ed. by Hartman, G.L.; Sinclair, J.B.; Rupe, J.C.) pp 25-26. APS, St Paul, Minnesota, USA.
ProMed postings. http:// www.promedmail.org
Phakopsora sp. Soybean rust – Nigeria (2001-03-09)
Phakopsora sp. Soybean rust – Africa (2001-03-09)
Phakopsora sp. Soybean rust – Africa (02) (2001-03-10)
Phakopsora sp. Soybean rust – South Africa (2001-03-13)
Phakopsora sp. Soybean rust – South Africa (confirmed) (2001-03-22)
Phakopsora sp. Soybean rust – South Africa (02) (2001-04-05)
Phakopsora euvitis, leaf rust, grapes - Australia (NT) (2001-08-03)
Phakopsora sp. Soybean rust – South Africa (03) (2001-12-13)
Phakopsora sp. Soybean rust – South Africa (2002-02-07)
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