Oregon State University Plant Clinic |
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Penicillium on stored garlic (Blue mold)Cause Penicillium hirsutum Dierckx (syn. P.corymbiferum Westling) Occurrence P. hirsutum seems to be the most common and widespread species occurring in storage. This disease occurs at harvest and in storage. Symptoms In storage, initial symptoms are seen as water soaked areas on the outer surfaces of scales. This leads to development of the green-blue, powdery mold on the surface of the lesions. When the bulbs are cut, these lesions are seen as tan or grey colored areas. There may be total deterioration with a secondary watery rot. Disease CyclePenicillium survives in infected bulbs and cloves from one season to the next. Spores from infected heads are spread when they are cracked prior to planting. If slightly infected cloves are planted, they may rot before plants come up, or the seedlings may not survive. The fungus does not persist in the soil. Air-borne spores often invade plants through wounds, bruises or uncured neck tissue. In storage, infection on contact is through surface wounds or through the basal plate; the fungus grows through the fleshy tissue and sporulation occurs on the surface of the lesions. Entire cloves may eventually be filled with spores. Management
ReferencesBertolini, P. & S.P. Tian, 1996. Low-temperature biology and pathogenicity of Penicillium hirsutum on garlic in storage. Postharvest Biology & Technology 7:83-89 Monnet, Y. & J. Thibault, 2001. Maladies et ravageurs de l'ail. Revue Horticole. 427:50-51 Overy, D.P., J.C. Frisvad, U. Steinmeier & U. Thrane, 2005. Clarification of the agents causing blue mold storage rot upon various flower and vegetable bulbs; implications for mycotoxin contamination. Postharvest Biology & Technology 35:217-221 Pscheidt, J. W., & C. M. Ocamb . Senior Editors. 2008. Pacific Northwest Plant Disease Management Handbook. Oregon State Extension Service. 642 pp. Rath, G.C. & G.N. Mohanty, 1979. Control of storage rot of garlic caused by three fungi. Pesticides XX:26-27 Schwartz, H.F. & Krishna Mohan, 2006. Compendium of onion and garlic diseases and pests, 2 nd Ed. APS Press UC IPM Online. Statewide Integrated Pest Management Guidelines. http://www.ipm.ucdavis.edu/PMG/r584101011.html WSU Profiles. Crop Profile for garlic in Washington . http://www.tricity.wsu.edu/~cdaniels/profiles/Garlic.pdf
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May 27, 2009
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