Association of Pine Wood Nematode with Stressed Trees in Minnesota, Iowa, and Wisconsin. M. J. Wingfield, Department of Plant Pathology, University of Minnesota, St. Paul 55108. R. A. Blanchette, Department of Plant Pathology, University of Minnesota, St. Paul 55108, T. H. Nicholls, North Central Forest Experiment Station, and K. Robbins, State and Private Forestry, U.S. Forest Service, St. Paul 55108. Plant Dis. 66:934-937. Accepted for publication 3 February 1982. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-934.

Trees infected with the pine wood nematode Bursaphelenchus xylophilus in Minnesota, Iowa, and Wisconsin were stressed by various forest diseases and insects. Nematodes were only found in trees already colonized by secondary insects such as bark beetles (Scolytidae) and borers (Cerambycidae). B. xylophilus was also found in dead tops or dead branches of otherwise healthy trees that appeared to have died as a result of fungal infection or insect attack. Typical wilt symptoms associated with B. xylophilus infection in Japan were not observed.

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