Incidence and Development of Verticicladiella procera in Virginia Christmas Tree Plantations. A. L. Lackner, Graduate Research Assistant, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. S. A. Alexander, Associate Professor, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. Plant Dis. 68:210-212. Accepted for publication 7 September 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-210.

The rates of incidence (r) of Verticicladiella procera in two Christmas tree plantations in Virginia were 0.17 and 0.049 from February to April 1980. During the summer, fall, and winter, r values decreased to near zero. By spring of 1981, r values were only 0.008 and 0.02 for the two plantations. Populations of V. procera in the soil were found to decline from August to October. The fungus was present in low numbers in the soil from October 1980 to June 1981. Many eastern white pines infected with V. procera were also infested with bark beetles. The fungus was isolated from 7% of bark beetles collected from six trees. Fifty diseased eastern white pines were cut in October 1980 and the stumps were excavated in April 1981. V. procera was isolated from 45% of the stumps, indicating that the fungus can overwinter in infected tree stumps. Mortality during this study averaged 26% in the two plantations.