ARS | Publication request: Embellisia Skin Blotch and Bulb Canker of Garlic

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 28, 2005
Publication Date: June 1, 2008
Citation: Dugan, F.M., Crowe, F. 2008. Embellisia skin blotch and bulb canker of garlic, pp.17-18 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 disease problems caused by Embellisia allii, a microscopic fungus. This deficiency is remedied in the second edition. The fungus is very common world-wide, but usually only causes a mild, superficial, charcoal-colored blemish that is readily removed by thorough washing. Occasionally the blemishes become severe enough to reduce the commercial value of the crop. More rarely, the disease progresses to an infection of the internal cloves, inducing a carbonaceous canker at the top or bottom of the cloves. In general, white-skinned garlic bulbs are more susceptible than those with reddish skins. The disease is promoted by excessive moisture during the later parts of the growing season and/or in storage. Chemical control is seldom used, but the fungicide thiram has proven effective under experimental conditions.

Technical Abstract: Embellisia allii, a hyphomycetous fungal pathogen of garlic (Allium sativum) is described in terms of microscopic morphology and host symptoms (skin blotch and bulb canker). Disease is worsened under conditions of excessive humidity during the latter part of the growing season or in storage. Growers can usually cope with the disease by washing bulbs and/or removal of some outer leaf sheaths, although the disease can progress to cankering of the cloves under extreme conditions. E. allii can overwinter in the soil and in infected bulbs. The fungicide thiram has been demonstrated to aid disease control when used as a pre-planting treatment.