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Effects of Inoculum Density and Wounding on Stem Infection of Three E astern US Forest Species by P hytophthora ramorum
Author(s) -
Tooley Paul W.,
Browning Marsha,
Leighty Robert M.
Publication year - 2014
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/jph.12251
Subject(s) - sporangium , phytophthora ramorum , biology , botany , inoculation , horticulture , pinus <genus> , spore , phytophthora
Seedlings of three E astern US forest species Q uercus rubra (northern red oak), Q uercus prinus (chestnut oak) and A cer rubrum (red maple) were inoculated by applying P hytophthora ramorum sporangia to stems at different inoculum densities with and without wounding. Disease occurred in all treatments involving wounds, and no disease was observed in unwounded treatments. Younger seedlings (2–3 years old) did not differ significantly from older seedlings (5–6 years old) in disease incidence, but older seedlings sustained smaller lesions compared with younger seedlings. For both old and young seedlings, disease on wounded stems was observed down to the lowest sporangia concentration utilized (500 sporangia/ml for old seedlings and 100 sporangia/ml for young seedlings). The results show that in the presence of wounding, even very low sporangia concentrations can result in disease, and further suggest that wounding caused by insects and other factors may play an important role in P . ramorum epidemiology in forest environments.