|Du Toit, L - WASHINGTON STATE UNIV|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 28, 2005
Publication Date: June 1, 2008
Citation: Du Toit, L.J., Dugan, F.M. 2008. Fusarium bulb rot of onion and garlic, pp.15-17 in: Compendium of Onion and Garlic Diseases and Pests, 2nd ed., edited by H.F. Schwartz and S.K. Mohan. APS Press, St. Paul, MN. Book Chapter. Interpretive Summary: The Compendium of Onion and Garlic Diseases, published by APS Press, is the primary reference for diseases and disorders of sweet onion and garlic. The first edition lacked a section on bulb rot caused by Fusarium proliferatum. This deficiency is remedied by the second edition. Fusarium proliferatum is related to Fusarium oxysporum f. sp. cepae and to Fusarium culmorum, but can be distinguished from these species on the basis of morphology and, to some extent, symptoms on the hosts. F. proliferatum can survive for extended periods of time in soil, so it is best to avoid repeatedly planting the same field with either onion or garlic. Using fludioxonil or thiophanate methyl as a pre-planting dip for cloves can bestow some protection.
Technical Abstract: Fusarium proliferatum is a hyphomycetous fungal pathogen with a wide host range, including onion and garlic. In garlic, invasion by the fungus results in water-soaked lesions, then a progressive tan-brown rot of the cloves. In onion, the fungus may be confined to the outer layers of the bulb, where it causes a pinkish blemish, or it may cause a deeper, necrotic brown rot. F. proliferatum can be distinguished from F. oxysporum f. sp. cepae and from F. culmorum on the basis of microscopic characters (chiefly, the formation of microconidia in chains by F. proliferatum) and to lesser extent by position and coloration of symptoms on the hosts.