Characterization and distribution of fungi associated with needle defoliation of eastern white pine (Pinus strobus).
S. A. WYKA (1), K. D. Broders (2), I. Munck (3). (1) University of New Hampshire, Dover, NH, U.S.A.; (2) University of New Hampshire, Durham, NH, U.S.A.; (3) USDA Forest Service, Durham, NH, U.S.A.
Eastern white pine is a crucial ecological and economic component of forests in the northern United States and eastern Canada and is facing an emerging problem with white pine needle defoliation (WPND). It is unclear whether WPND is caused by one or a combination of multiple fungal pathogens. Therefore, the objective of this study was to characterize the fungi associated with WPND in the Northeast United States. To date 51 species of fungi either cultured from diseased pine needles or from fruiting bodies on pine needles, were identified based on morphology and sequence data. The species most frequently recovered from diseased needles included <i>Lecanosticta acicola</i> (<i>Mycosphaerella dearnessii</i>), a historically southern pine pathogen, and a putative new species closely related to pine pathogen <i>Septorioides pini-thunbergii</i>. A multi-gene phylogenetic analysis of this new species placed the fungus in an entirely new genus and family within the Botryosphaeriales. This study also provides the first phylogenetic analysis of <i>Lophophacidium dooksii</i> (<i>Canavirgella banfieldii</i>) and <i>Bifusella linearis</i>, two obligate biotrophic fungi frequently observed on pine needles in the Northeast, for which no sequence data was previously available. As <i>L. acicola</i> appears to be the primary pathogen causing WPND, current research is investigating the epidemiology and role of climate on epidemics of WPND, as well as the potential northerly migration of <i>L. acicola</i> into northeastern pine populations.
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