New Conifer Hosts for Fusarium Root Rot in Pennsylvania. N. Wenner, Pennsylvania State University, University Park 16802. W. Merrill, Pennsylvania State University, University Park 16802. Plant Dis. 68:536. Accepted for publication 4 February 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-536b.
Root rot, associated with Fusarium solani (Mart.) App. & Wr. emend Synd., F. oxysporum Schl., and/or F. avenaceum (Fr.) Sacc., caused mortality in I- to 3-yr-old seedlings of Black Hills white spruce (Picea glauca (Moench) Voss), Colorado blue spruce (P. pungens Engelm.), eastern white pine (Pinus strobus L.), and eastern hemlock (Tsuga canadensis (L.) Carr.) in nursery seedbeds; 3- and 4-yr-old Colorado blue spruce and eastern white pine seedlings the first season after transplanting; and 2- and 3-yr-old container-grown Colorado blue spruce. Koch's postulates were completed with selected isolates of F. solani and F. oxysporum. Approximately 50% mortality also occurred over 1.62 ha of 3-yr-old Fraser fir (Abies fraseri (Pursh) Poir.) transplants from infested nursery seedbeds. Low survival rates (<60%) of seedlings of Colorado blue spruce, eastern white pine, Scots pine (Pinus sylvestris L.), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) following outplanting were associated with infection by these fungi in infested seedbeds.