J. H. Park, Division of Environmental Science and Ecological Engineering, Korea University, Seoul 136-701, Korea;
K. S. Han, Horticultural and Herbal Crops Environment Division, National Institute of Horticultural and Herbal Science, Suwon 441-440, Korea;
J. Y. Kim, Gyeonggi-Do Agricultural Research and Extension Services, Hwaseong 445-300, Korea; and
H. D. Shin, Division of Environmental Science and Ecological Engineering, Korea University, Seoul 136-701, Korea
Sansevieria, Sansevieria trifasciata Prain, is cultivated in greenhouses and is used as a potted interior foliage plant in Korea. In April 2012, several plants (cv. Moonshine) exhibiting typical anthracnose symptoms from a local nursery were sent to the plant clinic of Gyeonggi-Do Agricultural Research and Extension Services for diagnosis. The leaf lesions began as round, partly water-soaked, pale greenish to grayish spots, which enlarged and ultimately coalesced, resulting in severe leaf blight. Concentric rings of blackish acervuli were formed in the expanding lesions of mostly 2 to 4 cm in diameter. Acervuli were mostly epiphyllous, circular to ellipsoid. Setae were aseptate to 3-septate, dark brown at the base, paler upwards, acicular, and up to 180 μm long. Conidia (n = 30) were oblong-elliptical to obovate, sometimes fusiform-elliptical, guttulate, hyaline, and 14 to 24 × 5 to 7.5 μm (mean 18.6 × 6.4 μm). Hyphopodial appressoria were dark brown to blackish, globose to clavate in outline, and 5 to 12 × 4 to 8 μm. Colonies on potato dextrose agar (PDA) were grayish-white, felted with cottony-white aerial mycelium on a gray to olivaceous gray background in culture. Gelatinous salmon- to orange-colored conidial masses were produced abundantly after one week's incubation. The morphological and cultural characteristics of the fungus were consistent with the description of Colletotrichum sansevieriae M. Nakamura & M. Ohzono (2,3). A voucher specimen was deposited in the Korea University herbarium (KUS-F26637). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46835). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 569-bp sequences were deposited in GenBank (Accession No. KC847065). A BLAST search in GenBank exhibited 100% nucleotide identity with sequence of C. sansevieriae (JF911349) from the United States and >99% similarity with that of HQ433226 from Australia. To confirm pathogenicity, inoculum was prepared by harvesting conidia from 3-week-old cultures on PDA. A conidial suspension (2 × 106 conidia/ml) was sprayed over the five leaves of sansevieria ‘Moonshine’ wounded with a fine needle. Five leaves sprayed with sterile water served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 48 h and then kept in a greenhouse (22 to 28°C and 70 to 80% RH). Within 12 days, symptoms identical to those observed in originally infected leaf developed on all inoculated leaves. No symptoms were observed on control plants. C. sansevieriae was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. Sansevieria anthracnose associated with C. sansevieriae has been reported in Japan (2), Australia (1), and the United States (3). To our knowledge, this is the first report of sansevieria anthracnose in Korea. Our observations in sansevieria nurseries suggest that preventing wound infection as well as maintaining good plant hygiene in greenhouses might be main strategies for this disease.
References: (1) R. Aldaoud et al. Australas. Plant Dis. Notes 6:60, 2011. (2) M. Nakamura et al. J. Gen. Plant Pathol. 72:253, 2006. (3) A. J. Palmateer et al. Plant Dis. 96:293, 2012.