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Disease Note.

Pitch Canker of Pinus luchuensis in Japan. M. Muramoto, Kagoshima Prefectural Forest Experiment Station, Kamou-cho, Kagoshima, Japan. L. D. Dwinell, USDA Forest Service, Southeastern Forest Experiment Station, Athens, GA 30602. Plant Dis. 74:530. Accepted for publication 28 April 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0530B.

In the early 1980s, luchu pines (Pinus luchuensis Mayr.) on Amamiooshima and the Okinawa islands of Japan werc found with dieback of shoots and branches and with cankers on main stems. The xylem beneath cankers was deeply soaked with resin. In 1981, Fusarium subglutinans (Wollenw. & Reinking) Nelson, TouSloun, & Marasas was isolated from the bl eeding, resinous cankers. Because F. subglutinans is cosmopolitan and occurs on a wide range of hosts, isolates can be identified as the pitch canker pathotype only if their pathogenicity is demonstrated by inoculating pine seedlings (1). Pathogenicity of an isolate from a canker on P. luchuensis was revealed by inoculation to terminal shoots of 12 2·yr-old P. radiata and P. virginiana, on which lesions girdled the stems within 8 wk. An authentic isolate of the pitch canker pathotype of F. subglutinans (ATCC 52616) caused identical symptoms on other seedlings in the same experiment, whereas controls remained free from symptoms. Therefore, F. subglutinans from luchu pine in Japan is the pitch canker pathotype.

Reference: (1) L. D. Dwinell et al. Plant Dis. 69:270, 1985.