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|Title:||Brown Root Rot Disease in American Samoa's Tropical Rain Forests|
|Authors:||Brooks, Fred E.|
|Publisher:||University of Hawai'i Press|
|Citation:||Brooks FE. 2002. Brown root rot disease in American Samoa's tropical rain forests. Pac Sci 56(4): 377-387.|
|Abstract:||Phellinus noxius (Corner) Cunningham causes root and lower stem rot
of woody plants throughout the South Pacific region. Its hosts include rubber,
mahogany, cacao, and many timber, fruit, and landscape trees. Though endemic
to the Tropics, no reports were found describing brown root rot disease in native
forests, exclusively. Incidence, distribution, and host range of P. noxius were
measured in primary and secondary rain forests on Tutuila Island, American
Samoa. Phellinus noxius was recorded in 19 of 20 strip transects and 1.2-ha established
plots and in all vegetation types, infecting 37 tree species in 30 genera
and 22 families. Species most affected were Myristica Jatua, Dysoxylum samoense,
and Hibiscus tiliaceus-25, 16, and 10%, respectively. Of 62 infection centers,
33 contained the same tree species and 13 were dominated by a single species.
The fewest infections were recorded at primary montane and ridge top sites.
Regenerating secondary valley sites had the highest incidence of disease and
greatest number of infection centers. Infection centers at these disturbed sites
also contained more trees on average than centers at primary sites. Disease incidence
was influenced more by human disturbance than by vegetation type,
topography, stem diameter, stem density, or soil type. The disturbed sites also
appeared to lack the species richness of mature sites. This agrees with other
host/pathogen associations, such as Douglas-fir/P. weirii and hardwood/Po noxius
plantations, where disease incidence and spread was higher in species-poor
than in species-rich stands.
|Appears in Collections:||Pacific Science Volume 56, Number 4, 2002|
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