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Root Disease and Insect Infestations on Air-Pollution-Sensitive Pinus strobus and Studies of Pathogenicity of Verticicladiella procera. A. L. Lackner, Graduate Research Assistant, Virginia Polytechnic Institute and State University, Blacksburg 24061. S. A. Alexander, Associate Professor, Virginia Polytechnic Institute and State University, Blacksburg 24061. Plant Dis. 67:679-681. Accepted for publication 1 December 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-679.

Two lateral roots were excavated from each of 25 air-pollution-sensitive and 18 air-pollution-tolerant eastern white pines in the Blue Ridge Mountains in Virginia. Verticicladiella procera, Heterobasidion annosum, V. serpens, and a Graphium sp. were isolated from 24, 8, 8, and 4% of the sensitive trees, respectively. Two species of weevils, Pissodes approximatus and a Hylobius sp., were isolated from 20% of the sensitive trees. No pathogenic fungi or insects were isolated from the tolerant trees. The pathogenicity of three V. procera isolates was tested on eastern white pine and loblolly pine seedlings. Seedlings were inoculated using a root-dip method. Fifty-nine of 60 eastern white pines and 57 of 60 loblolly pines were dead 7 wk after inoculation. The total number of eastern white pines and loblolly pines killed was not significantly different (P = 0.05). One isolate killed significantly fewer loblolly pines than eastern white pines (P = 0.05).