Poster Session: New and Emerging Diseases-Fungi and Oomycetes

416-P

Survey of wood decay fungi of Casuarina equisetifolia (ironwood) on the islands of Guam and Saipan.
R. L. SCHLUB (1), R. C. Mendi (1), C. C. Aiseam (1), R. C. Mendi (1), J. K. Davis (1), M. C. Aime (2)
(1) University of Guam, Mangilao, Guam; (2) Louisiana State University, Baton Rouge, LA, U.S.A.

As a result of statistical modeling of data from individual trees and tree sites, the occurrence of basidiocarps consistently emerged as the dominant explanatory variable for Guam’s declining ironwood trees (Casuarina equisetifolia). A survey was conducted in February 2012 in the Mariana Islands to elucidate which of the known basidiocarp-forming genera are most consistently correlated with the decline. Species from five basidiomycete genera of the class Agaricomycetes, belonging to the orders Polyporales (Ganoderma, Favolus, Pycnoporus), Hymenochaetales (Phellinus) and Thelephorales (Sarcodon) were previously identified from Guam based on macro- and micromorphology and DNA sequencing. As a result of the February survey, Ganoderma sp. (G. australe complex) was the basidiocarp found to be most frequently associated with unhealthy trees. Conks of the fungus were commonly found on Guam where they appeared on roots and butts of declining and stumps of dead trees. On Saipan where decline does not exist and where the trees are considerably healthier, Ganoderma sp. was rarely found. In contrast, Phellinus sp. was the most widespread fruiting basidiocarp on Guam and Saipan. Though the actual species of Phellinus remains to be determined, it does not appear to represent P. noxious, and is not consistently associated with trees in decline. These and other species associated with ironwood trees in the Mariana Islands will be discussed.