Chinese woad (Isatis indigotica) is a biennial herb in the Brassicaceae that is widely cultivated in China. Extracts from the roots and leaves have potential pharmaceutical use for treatment of flu, encephalitis, measles, hepatitis, and mumps (2). In June 2012, a leaf spot was observed on 1-year-old plants of I. indigotica in the medicinal garden of Jilin Agricultural University, Changchun, Jilin Province, China. More than 50% of the leaves and 100% of the plants in the garden were symptomatic. In the initial stage of infection, irregular to circular, dark gray spots, each surrounded by a chlorotic halo, appeared on leaves. The spots ranged from pinpoint to 5 mm in diameter. Some spots enlarged and coalesced, forming concentric rings. Black, sunken, fusiform lesions were observed on the petioles. Lesions gradually dried and exhibited a shot-hole appearance, and entire infected leaves desiccated. Small pieces of infected leaves and petioles were surface-disinfested in 75% ethanol for 60 s, rinsed thrice in sterilized distilled water, dried, and plated on potato dextrose agar. Olive-green mycelium developed after 2 days of incubation at 25°C, turned dark green, and covered the petri dish 10 days later. The periphery of each colony was gray and velvety. On potato carrot agar medium, conidia formed on branched chains. Conidiophores arose singly or in clusters, were straight or flexuous, separated, and measured 6.8 to 26.7 × 3.1 to 11.9 μm Conidia on host plant tissues were olivaceous, cylindrical or inverted clavate, and 25.8 to 65.2 × 10.9 to 18.3 μm Larger conidia were cylindrical or obclavate, and smaller conidia were oval. Transverse and longitudinal septa of conidia ranged from 3 to 10 and from 0 to 7 μm, respectively. A very small conidial beak or no beak was observed on each conidium. On the basis of these morphological characteristics,the fungus was identified as Alternaria brassicicola (3). A PCR assay with the ITS4 and ITS5 primers was used to amplify DNA extracted from each of four isolates (1). The sequence (567 bp) of isolate Sl-8 was submitted to GenBank (Accession No. KF531832), and showed 100% similarity to that of an A. brassicicola isolate (AF392985.1), confirming the species identification. Pathogenicity assays with 10 single-conidium isolates were done by spraying a conidial suspension (1 × 106 conidia/ml) of each isolate, or sterilized water for the control treatment, onto healthy leaves and petioles of five 3-month-old plants of I. indigotica. Inoculated and control plants were enclosed in plastic bags for 48 h. After 7 days, symptoms on inoculated plants were similar to those on the original diseased plants, while control plants remained symptomless. Re-isolation from inoculated plants produced mycelial colonies with morphological characteristics of A. brassicicola, fulfilling Koch's postulates. No fungus was isolated from control plants. A. napiformis and A. brassicae have been reported as causal agents of Alternaria leaf spot on I. indigotica in China (3). To our knowledge, however, this is the first report of A. brassicicola as a pathogen on I. indigotica in China. References: (1) N. L. Glass and G. C. Donaldson. Appl. Environ. Microbiol. 61:1323, 1995. (2) A. J. Li et al. Flora Reipublicae Popularis Sinicae Tomus 33, 1998. (3) T. Y. Zhang. Alternaria. Pages 99-100 in: Flora Fungorum Sinicorum, 2003.

Rheum rhabarbarum L., rhubarb, is a perennial herb planted mainly in Hebei, Hubei, Shanxi, Heilongjiang, and Jilin provinces as well as Inner Mongolia, China. The plant grows about 1,000 meters above sea level (4), and is used widely in China to treat constipation and gout. From June to September 2012, a leaf spot was observed on R. rhabarbarum in the medicinal garden of Jilin Agricultural University, Changchun, Jilin Province, causing significant effects on the leaves of all infected plants. In the early stage of disease development, small red lesions were visible on infected leaves, which subsequently developed into irregularly shaped or circular necrotic spots, each with a light colored center, pink-red alternating concentric rings, and surrounded by a chlorotic halo. Some lesions became perforated in the center. Lesions ranged from 1 to 15 mm in diameter. Extensive spotting resulted in general browning and yellowing of entire leaves. As lesions enlarged and coalesced, some leaves died from the margin inwards. Lesions on the stem were fusiform and sunken. Small pieces of diseased leaves and stems were surface-disinfested in 75% ethanol for 60 s, rinsed twice in distilled water, dried, and plated on potato dextrose agar (PDA). A Phoma species was isolated that produced a gray or dark gray colony after 5 to 7 days. The isolate was transferred to oatmeal agar (OA) (3). Pycnidia were dark brown to black, globose to subglobose, and 121 to 354 × 100 to 262 μm. Conidia were ellipsoidal or reniform, colorless, unicellular, and 3.8 to 6.5 × 1.7 to 4.1 μm. On the basis of these characteristics, the fungus was identified as Phoma rhei (1). A PCR assay with the ITS4 and ITS5 primers was used to amplify the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) (2). The amplified product (567 bp) was sequenced and the sequence submitted to GenBank (Accession No. KF531831). The ITS sequence exhibited 99% identity to that of a P. rhei isolate in GenBank (GU237743.1), confirming the morphological identification. Pathogenicity of eight isolates on rhubarb was confirmed by spraying a spore suspension (1 × 106 spores/ml) produced on PDA on the leaves of each 6-year-old R. rhabarbarum (cv. Boyedahuang) plant. Each isolate was inoculated onto five plants, and five plants were sprayed similarly with sterilized water as a control treatment. The plants were then covered with plastic bags for 48 h, and kept in a greenhouse (20 to 30°C with a 12-h photoperiod/day). Initial symptoms on inoculated leaves were observed 3 to 4 days after inoculation, while the control plants remained healthy. Re-isolations from lesions on the inoculated leaves, using the same protocol as the original isolations, produced fungal colonies with the same morphological characteristics as the original isolates of P. rhei, but no fungi were re-isolated from the control plants. This fungus has been found on R. rhaponticum in New Zealand (1), but to our knowledge this is the first report of P. rhei on R. rhabarbarum in China. References: (1) G. H. Boerema et al. Phoma Identification Manual. Diffferentiation of Specific and Infra-Specific Taxa in Culture. CABI Publishing. Wallingford, UK, 2004. (2) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (3) Z. D. Fang. Research Method of Phytopathology. China Agricultural Press (In Chinese), 1998. (4) A. J. Li et al. Flora Reipublicae Popularis Sinicae. Tomus 25:171, 1998.

Horn lian (Typhonium giganteum) is a perennial herb of the family Aracea and is commonly used for expelling phlegm and as an antispasmodic treatment. In August 2012, horn lian grown in Changchun, Jilin Province of China, exhibited soft rot disease with ~60% incidence and experienced great losses. Water-soaked and dark green lesions on leaves expanded along main veins. Semitransparent, water-soaked, and sunken lesions on stems expanded rapidly and caused the whole plant to collapse with a foul smell. Nine representative strains were isolated from infected leaves and stems on nutrient agar (NA) medium after 36 h incubation at 28°C (1). Colonies were round, shiny, grayish white, and convex on NA medium. All strains were gram-negative, non-fluorescent on King's B medium (KB), facultatively anaerobic, motile with three to six peritrichous flagella (observed by electron transmission microscope), positive for catalase and pectolytic activity test on potato slices, but negative for oxidase, urease, and lecithinase. Strains grew at 37°C and in yeast salts broth medium containing 5% NaCl. They also liquefied gelatin and reduced nitrate, but did not reduce sucrose. Strains were also negative for starch hydrolysis, malonate utilization, gas production from glucose and indole. Results were variable for the Voges-Proskauer test. The strains utilized sucrose, arabinose, fructose, D-galactose, D-glucose, inositol, lactose, D-mannose, D-mannitol, melibiose, rhamnose, salicin, trehalose, maltose, raffinose, glycerol, D-xylose, and cellobiose as carbon sources, but not melezitose, α-CH3-D-gluconate, sorbitol, or dulcitol. Species identity was confirmed by molecular characterization of one of the nine strains, DJL1-2. DNA GC content indicated by high performance liquid chromatography (HPLC) was 51.7%. The 16S rDNA sequence (KC07897) of DJL1-2 showed 99% identity to that of a Pectobacterium carotovorum subsp. carotovorum (Pcc) strain (CP001657) and the sequence of the 16S-23S rDNA spacer region (KJ623257) was 93% similar to that of another known strain of Pcc (CP003776). As a result, the strains were identified as Pcc (2). Pathogenicity of the nine strains was evaluated by spraying 1 ml of bacterial cell suspension (108 CFU/ml) onto healthy leaves and injecting 0.1 ml of cell suspension into stems of 3-year-old horn lian plants with a sterile pipette tip. Three seedlings were used for each strain and sterilized water served as negative controls. Pcc SMG-2 reference strain (from milk thistle) was also inoculated into horn lian leaves and stems. Inoculated plants were covered with plastic bags for 24 h in a greenhouse at 28 to 30°C. After 72 h, water-soaked lesions similar to the naturally infected plants were observed on leaves and stems inoculated by the nine isolated strains and Pcc SMG-2, while negative control plants remained symptomless. Biochemical tests and 16S rDNA sequence analysis confirmed that the re-isolated bacteria were Pcc. To our knowledge, this is the first report of Pcc causing bacterial soft rot of horn lian in Changchun, Jilin Province, China. References: (1) Z. D. Fang. Research Method of Phytopathology. China Agricultural Press, 1998. (2) N. W. Schaad, et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria, 3rd ed. American Phytopathological Society, St. Paul, MN, 2001.

The foliage of severely affected plants was stunted and wilted. The disease affected 5 ha and incidence was approximately 30%. Cream-colored bac terial colonies were isolated from surface disinfested symptomatic tissue that was macerated and streaked onto King's medium B (KMB) and su crose peptone agar (SPA). Fungi were not recovered from any tissue that was surface disinfested and placed into acidified potato dextrose agar. Four representative strains were fluorescent on KMB and gram-negative based on lysis by KOH. Strains were positive for levan formation, negative for oxidase and arginine dihydrolase, and did not cause soft rot on potato slices but induced a hypersensitive response in tobacco (Nicotiana tabacum L. cv. Samsun); strains thus belonged to Lelliot's LOPAT group 1, P. syringae (3). All four strains had identical DNA fragment-banding patterns generated by repetitive extragenic palindromic sequence (rep)-PCR using the BOXA1R primer (4). The pattern generated was different than all P. syringae pathovars in genomospecies 1 including P. syringae pv. syringae. According to multilocus sequence analysis conducted by previously de scribed methods, the strains are most closely related to P. syringae pv. aceris and P. syringae pv. solidagae in genomospecies 1 (1). Potted rasp berry plants were used to test four strains for pathogenicity. Inoculum was prepared by growing the bacteria on SPA for 48 h and suspending the bacteria in sterile distilled water (SDW) for a final concentration of ap proximately 107 CFU/ml. Suspensions were sprayed until runoff onto three replicate plants per strain. Control plants were sprayed with SDW until runoff. Plants were enclosed in plastic bags for 24 h and then main tained in a greenhouse (23 to 25°C). After 7 to 8 days, water soaked le sions developed on all inoculated plants; lesions later turned dark brown and appeared similar to symptoms observed in the field. Plants treated with water developed no symptoms. Bacteria re-isolated onto KMB from symptomatic tissues were fluorescent and appeared identical to the bacte ria used to inoculate the plants; two selected re-isolated strains were iden tical to the original strains according to rep-PCR, fluorescence, and LOPAT reactions. The experiment was repeated and disease development and recovery of fluorescent strains on KMB was identical to the first ex periment. To our knowledge, this is the first report of Pseudomonas blight of raspberry, caused by P. syringae, in California. Affected plants initially were stunted in growth but later in the summer exhibited no lasting effects from the disease. Pseudomonas blight has been reported in the Pacific Northwest region of the United States, the British Columbia region of Canada, and Serbia (2). Carrot(Daucus carota L. subsp. sativus [Hoffm.] Arcang.) is an im portant vegetable in Serbia, where it is grown on nearly 8,000 ha. In Au gust 2012, -1 ,5 0 0 ha o f carrot fields were inspected in southern Backa in North Serbia. In nearly 40% o f the fields, severe foliar and stem symptoms cha...

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