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Disease Note.

First Report of the Occurrence of Bipolaris maydis on Bermudagrass. Wen- Shi Wu, Department of Plant Pathology National Taiwan University, Taipei, Taiwan. Yuen-Ping Wang, Department of Entomology, National Taiwan University, Taipei, Taiwan. Plant Dis. 78:926. Accepted for publication 24 May 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0926C.

Bipolaris maydis (Nisikado & Miyake) Shoemaker was isolated from bermudagrass (Cynodon dactylon (L.) Pers.) in northern Taiwan. The symptoms of the infected plants were reddish brown to dark brown ne crotic lesions. When lesions enlarged, they became oblong and coalescent. Conidia produced from infected bermudagrass leaves were similar to those reported for B. maydis infecting maize (Zea mays L.), averaged 16.8 ?m wide by 142 ?m long, and were dark brown in color. Conidia used to inoculate bermudagrass were cultured on sterilized corn and bermudagrass leaves. Six hours after inoculation, spores germinated bipolarly, and penetrated and colonized the leaves both inter- and intracellularly. After 4 days at 25 C with diurnal light (12/12 hr) and high humidity (>90%), inoculated leaves developed dark striped lesions similar to those observed on naturally infected bermudagrass. Conidia collected and fungus isolated from infected leaves were identical to the original isolates from naturally infected bermudagrass leaves. Conidia collected from sterilized corn leaves, bermudagrass leaves, or corn leaf or bermudagrass leaf dextrose agar (20 g of corn or bermudagrass leaves, 20 g of dextrose, and 20 g of agar in 1 L of distilled water) caused significantly (P = 0.05) more lesions on bermudagrass than did the conidia collected from potato-dextrose agar. The same fungus caused water-soaked circular lesions on corn leaves after 24 hr of incubation and rapidly developed typical lesions of southern corn leaf blight. Moreover, the isolate from bermudagrass also infected Coix lacryma-jobi L., Digitaria radicosa (Presl.) Miq., Echinochloa crus-galli (L.) P. Beauv. var. formosensis Ohwi, E. crus-galli var. praticola Ohwi, Eleusine indica (L.) Gaertn., Paspalum dilatatum Poir., Sorghum bicolor (L.) Moench, and Zoysia matrella (L.) Merr.