Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/25/2007
Publication Date: 1/1/2008
Citation: Mukhina, Z.M., Kassanelly, D., Kolomiets, T.M., Berner, D.K., Dubin, H. 2008. First report of leaf spot caused by Cercospora bizzozeriana on hoary cress in Russia. Plant Disease. 92:316. Interpretive Summary: Hoary cress or white top is a target of biological control efforts in the U.S. Diseased and dying hoary cress plants were found near Kugoyeyskoye, Krylovskoy area, Krasnodar region of Russia, and the fungus Cercospora bizzozeriana was determined to cause the disease. In the laboratory, it was found that this fungus readily caused disease and significant damage on hoary cress, and that this particular fungus has potential as a biological control agent of hoary cress.
Technical Abstract: In the summer of 2006, dying hoary cress (Lepidium draba subsp. draba) plants were found around Kugoyeyskoye, Krylovskoy area, Krasnodar region of Russia. Plants had grayish-white leaf spots on most of the leaves. In most cases the leaf spots coalesced, and the leaves wilted and died. The fungus isolated from the leaf spots conformed to the description of Cercospora bizzozeriana, which was re-isolated from all plants inoculated with the fungus. DNA sequences of the ITS1 and ITS2 regions and the 5.8S ribosomal RNA gene aligned perfectly with the same sequences of another isolate of this fungus collected from hoary cress in Tunisia. Both isolates of C. bizzozeriana are destructive pathogens on hoary cress and locally severe epidemics have been observed in both Russia and Tunisia. This fungus has been reported in North America, and a North American isolate would be a good candidate as an inundative biological control agent to control this invasive weed. To our knowledge, this is the first report of C. bizzozeriana on hoary cress in Russia.