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The herbaceous perennial Lepidium draba L. is an invasive weed of rangelands and riparian areas in North America and Australia. As of 2002, it had infested 40,500 ha of rangeland in Oregon and large areas in Wyoming and Utah. Little is known of plant pathogens occurring on L. draba, especially in the United States, that could be useful for biological control of the weed. Leaf spots were first noted on a stand of L. draba near Shepherd, MT in 1997. The spots were mostly circular but sometimes irregularly shaped and whitish to pale yellow. The pathogen was erroneously assumed to be Cercospora beticola since its morphological traits closely resembled that species and the area had large fields of sugar beet with heavy Cercospora leaf spot incidence. Diseased leaves of L. draba were collected in 1997 and 2007. Conidia, borne singly on dark gray, unbranched conidiophores produced on dark stromata late in the season, were elongate, hyaline, multiseptate, 38 to 120 × 2 to 6 μm (mostly 38 to 50 × 2 to 5 μm) and had bluntly rounded tips and wider, truncate bases. These characteristics were consistent with the description of C. bizzozeriana Saccardo & Berlese (2). To isolate the fungus, spores were picked from fascicles of conidiophores with a fine-tipped glass rod, suspended in sterile water, and spread on plates of water agar. Germinated spores were transferred to potato dextrose agar (PDA). The ITS1, 5.8S, and ITS2 sequences of this fungus (GenBank Accession No. EU887131) were identical to sequences of an isolate of C. bizzozeriana from Tunisia (GenBank Accession No. DQ370428). However, these sequences were also identical to those of a number of Cercospora spp. in GenBank, including C. beticola. We also compared the actin gene sequences of the Montana isolate of C. bizzozeriana (GenBank Accession No. FJ205397) and an isolate of C. beticola from Montana (GenBank Accession No. AF443281); the sequences were 94.6% similar, an appreciable difference. For pathogenicity tests, cultures were grown on carrot leaf decoction agar. Aqueous suspensions of 10 4 spores per ml from cultures were sprayed on 6-week-old L. draba plants. Plants were covered with plastic bags and placed on the greenhouse bench at 20 to 25°C for 96 h. Koch's postulates were completed by reisolating the fungus from the circular leaf spots that appeared within 10 days, usually on lower leaves. Spores of C. bizzozeriana were also sprayed on seedlings of sugar beet, collard, mustard, radish, cabbage, and kale under conditions identical to those above. No symptoms occurred. After the discovery of the disease in 1997, plants of L. draba in eastern Montana, Wyoming, and Utah were surveyed from 1998 to 2003 for similar symptoms and signs, but none were found. This, to our knowledge, is the first report of C. bizzozeriana in the United States. The initial report of the fungus in North America was from Manitoba in 1938 (1). It has recently been reported as occurring on L. draba in Tunisia (4) and Russia (3) and is reported as common in Europe (2). A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI No. 878750A). References: (1) G. R. Bisby. The Fungi of Manitoba and Saskatchewan. Natl. Res. Council of Canada, Ottawa, 1938. (2) C. Chupp. A Monograph of the Fungus Genus Cercospora. C. Chupp, Ithaca, NY, 1953. (3) Z. Mukhina et al. Plant Dis. 92:316, 2008. (4) T. Souissi et al. Plant Dis. 89:206, 2005.

Hoary cress (Lepidium draba (L.) subsp. draba (synonym = Cardaria draba (L.) Desv.) (1), family Brassicaceae, is a common weed in Russia but it is an aggressive invasive weed in the northwestern United States. In the summer of 2006, dying hoary cress plants were found near Kugoyeyskoye in the Krylovskoy area of the Krasnodar Region of Russia. Plants had grayish white leaf spots on most of the leaves. In some cases, the diseased leaf spots dropped out of the leaves producing shot-holes. In most cases, the leaf spots coalesced and the leaves wilted and died. Diseased leaves were collected, air dried, and sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit (FDWSRU), USDA/ARS, Fort Detrick, MD. The air-dried leaves were observed microscopically, and numerous conidiophores and conidia were observed on both sides of leaves within and around the lesions. The fungus isolated (DB06-018) conformed to the description of Cercospora bizzozeriana Saccardo & Berlese (2). Conidiophores were 1 to 5 geniculate, unbranched, pale olive-brown, and uniform in color and width (4 μm). Conidia were multiseptate, hyaline, cylindric, straight to slightly curved, and measured 57 to 171 μm (average 103) long × 3.8 to 6.7 μm (average 4.6) wide. Leaves of rosettes (10 to 15 cm in diameter) of four hoary cress plants were spray inoculated with an aqueous suspension of conidia (1 × 10 5 /ml) and mycelia harvested from 6- to 8-day-old cultures grown on V8 medium. Inoculated plants and two noninoculated plants were placed in a dew chamber at 20°C in darkness and continuous dew. After 96 h, plants were moved from the dew chamber to a greenhouse bench. All plants were watered twice daily. After 12 days, symptoms were observed on all inoculated plants. Symptoms were identical to those observed in the field in Russia. No symptoms were observed on noninoculated plants. C. bizzozeriana was reisolated from the leaves of all symptomatic plants. Nucleotide sequences were obtained for the internal transcribed spacer regions ITS1 and ITS2 and the 5.8S ribosomal RNA gene (GenBank Accession No. EU031780) and aligned with the same sequences obtained from another C. bizzozeriana isolate (GenBank Accession No. DQ370428) collected in Tunisia. There was 100% alignment of the two sequences with no gaps. Both isolates of C. bizzozeriana are destructive pathogens on hoary cress and locally severe epidemics have been observed in both Russia and Tunisia (4). This fungus has also been reported in North America (3) and has the potential as a biological control agent where the weed is a problem. To our knowledge, this is the first report of C. bizzozeriana on L. draba subsp. draba in Russia. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878175). Live cultures are being maintained at FDWSRU. References: (1) I. A. Al-Shehbaz and K. Mummenhoff. Novon 12:5, 2002. (2) C. Chupp. A Monograph of the Fungus Genus Cercospora. C. Chupp, Ithaca, New York, 1953. (3) I. L. Conners. Res. Bra. Can. Dep. Agric. 1251:1, 1967. (4) T. Souissi et al. Plant Dis. 89:206, 2005.