Fusarium foetens: addition to the EPPO Alert List
Considering the recent findings of Fusarium foetens, a new disease of Begonia x hiemalis (Begonia Elatior hybrids) in several European countries and USA, the EPPO Secretariat felt that it could usefully be added to the Alert List.
Fusarium foetens (a new disease of begonia)
Why: Fusarium foetens was first found and described as a new species of Fusarium (different from F. begoniae) attacking Begonia x hiemalis (Begonia elatior hybrids) in the Netherlands. This species was then reported in USA and Germany. The origin of this new disease is unknown. F. foetens was intercepted a few times on traded cuttings and pot plants in Europe, showing that it had the potential to be spread via trade.
Where: Netherlands (first found in 2000), Germany (first found in 2001, and occasionally since then in Sachsen-Anhalt, Schleswig-Holstein, Nordrhein-Westfalen, Niedersachsen), USA (in 2003 and 2004, it was found on Begonia x hiemalis in Connecticut).
On which plants: So far, F. foetens has only been found on cultivars of Begonia x hiemalis. Data is lacking on its host range, and on the susceptibility of Begonia x hiemalis cultivars and of other ornamental species. Preliminary studies have shown that F. foetens was not a pathogen of other ornamentals, such as Saintpaulia ionantha, Impatiens New Guinea hybrids and Euphorbia pulcherrima. When inoculated, Cyclamen persicum plants did not develop the disease but showed discoloured vessels from which the fungus could be re-isolated.
Damage: Diseased plants showed basal rot, vein yellowing and wilting. Large macroconidial masses formed by the fungus covered the base of collapsing begonias. In nurseries, the disease was reported as severe and mortality of the plants has been observed. More data is needed on the economic impact of this disease.
Pictures can be viewed on Internet:
Dissemination: F. foetens produces several types of spores which ensure natural spread over short distance: microconidia (spread by water), macroconidia (spread by air and water) and chlamydospores (survival in soil). Over long distances, trade of infected plants or soil can spread the disease. So far, no teleomorph has been observed.
Pathway: Plants for planting (cuttings), pot plants, soil.
Possible risks: Begonias are valuable glasshouse crops in many European countries. Control of vascular diseases caused by Fusarium is difficult in practice (it relies on a combination of various methods, such as chemical control, disinfection and hygiene measures). So far, no data is available on the possible existence of tolerant/resistant cultivars. At an early stage of the disease, F. foetens is difficult to detect by visual inspection. Although the origin of F. foetens remains unknown (was it introduced from another part of the world?), it appears clearly that this pathogen can be moved through trade within Europe, and has the potential to establish in glasshouse conditions and damage begonia crops.
EPPO RS 2005/111
Panel review date - Entry date 2005-08
Elmer WH, Vossbrinck C, Geiser DM (2004) First report of a wilt disease of Hiemalis Begonias caused by Fusarium foetens in the United States. Plant Disease 88(11), p 1287.
Schroers HJ, Baayen RP, Meffert JP, de Gruyter J, Hooftman M, O'Donnell K (2003) Fusarium foetens, a new species pathogenic to begonia elatior hybrids (Begonia x hiemalis) and the sister taxon of the Fusarium oxysporum species complex. Mycologia 96(2), 393-406.
APS website, USA.
Elmer WH, Vossbrinck C, Geiser DM (2004) Fusarium wilt of Hiemalis begonia caused by Fusarium foetens. Northeastern Division Meeting Abstracts, 2004-10-06/08 - State College, Pennsylvania, US. http://www.apsnet.org/meetings/div/ne04abs.asp
Landwirtschaftskammer Nordrhein Westfalen, Pflanzenschutzdienst, Germany.
Powerpoint presentation by R. Schrage, Begonientag 2004-09-15, Hannover-Ahlem, Germany. http://www.pflanzenschutzdienst.de/pdf/be/Zier/Begonien_H_04.pdf