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Disease Control and Pest Management

Mycoparasitic Effects of Scytalidium uredinicola on Aeciospore Production and Germination of Cronartium quercuum f. sp. fusiforme. E. G. Kuhlman, Principal plant pathologist, USDA Forest Service, Southeastern Forest Experiment Station, Forestry Sciences Laboratory, Research Triangle Park, NC 27709; Phytopathology 71:186-188. Accepted for publication 7 July 1980. 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, 1981. DOI: 10.1094/Phyto-71-186.

Maximum aeciospore production by Cronartium quercuum f. sp. fusiforme on 10 loblolly pines averaged 111 × 10³ spores per square millimeter of gall tissue. In areas of the same galls parasitized by Scytalidium uredinicola, aeciospore production was reduced 72% to 31,000 spores per square millimeter. Rapid dispersal decreased the aeciospore population on nonparasitized and parasitized gall tissues to 13 and 23%, respectively, of the maxima after 1 wk. Germination of aeciospores from heavily parasitized gall areas was significantly reduced compared with that from nonparasitized or lightly parasitized areas. Although significant differences in aeciospore germination occurred among sampling dates during the sporulation seasons, no linear relationship was detected between germination and time.