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Disease Note.

Armillaria ostoyae Associated with Mortality of New Hosts in Chihuahua, Mexico. C. G. Shaw III, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO 80526. . Plant Dis. 73:775. Accepted for publication 24 May 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0775B.

Armillaria sp. was found on dying Pseudotsuga menziesii (Mirb.) Franco, Abies durangensis Martinez, Pinus ayacahuite Ehrenb., and P. arizonica Engelm. in a natural forest at 2,400 m north of Tomochic, Chihuahua, Mexico. Cultures were obtained from colonized wood of A. durangensis and P. menziesii and grown in flasks containing autoclaved orange halves covered with liquid malt extract (3%) under a controlled temperature/light regime (1). Fruiting bodies that fit morphological criteria for Armillaria ostoyae (Romagn.) Herink developed after 3 mo in two isolates from P. menziesii and one from A. durangensis. The two isolates from A. durangensis were confirmed to be A. ostoyae by cultural pairings with known diploid isolates (G. McDonald, personal communication). Armillaria sp. was previously found in plantations of P. arizonica and P. radiata D. Don in Chihuahua (F. G. Hawksworth in: Proc. Nac. Parasitol. For. IV 1987). This appears to be the first report of Armillaria on P. ayacahuite or A. durangensis.

Reference: (1) V. R. Siepman. Eur. J. For. Pathol. 15:71, 1985.