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Techniques

Spore Production and Artificial Inoculation Techniques for Gremmeniella abietina. M. Marosy, Department of Plant Pathology (Marosy and Patton) and ARS/USDA and Department of Plant Pathology (Upper), University of Wisconsin, Madison 53706, Current address: USDA–Forest Service, Forest Pest Management, 630 Sansome St., San Francisco, CA 94111; R. F. Patton, and C. D. Upper. Department of Plant Pathology (Marosy and Patton) and ARS/USDA and Department of Plant Pathology (Upper), University of Wisconsin, Madison 53706. Phytopathology 79:1290-1293. Accepted for publication 20 June 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1989. DOI: 10.1094/Phyto-79-1290.

Viable conidia of Brunchorstia pinea (teleomorph = Gremmeniella abietina) were produced in flasks containing 20% V-8 broth incubated at 16–18 C under a 16-hr photoperiod with a light intensity of approximately 100 µE m^–2 sec^–1. More than 6 × 10⁷ spores per flask were usually produced in 21 days under these conditions. Red pine seedlings were inoculated with a suspension of conidia that had been produced in this way, held at 18 C at high relative humidity for 3 days, and transferred to 4 C. Disease symptoms of Scleroderris shoot blight, as indicated by loose fascicles, appeared after as few as 56 days in the dark at 4 C.