TITLE Phytoplasmas are not associated with quick decline of macadamia trees in Hawaii
AUTHOR Ing-Ming Lee
Molecular Plant Pathology Laboratory, Agriculture Research Service, USDA, Beltsville, Maryland 20705, USA
Wen-Hsiung Ko
Department of Plant Pathology, Beaumont Agricultural Research Center, University of Hawaii at Manoa, Hilo, Hawaii 96720, USA
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ABSTRACT Association of phytoplasma with quick decline of macadamia trees in Hawaii was reevaluated. Twenty samples were collected from symptomatic and symptomless trees of the two susceptible cultivars cv. 333, and cv. 344 grown at Keaau and Kaiwiki on the island of Hawaii. Ultrasensitive nested-PCR assays using two universal primer pairs failed to detect phytoplasmas in all samples tested, contradicting the recent reports that phytoplasma may play a role in macadamia decline or quick decline. In contrast, infection of trunks by two fungal pathogens, Nectria rugulosa and Xylaria arbuscula were consistently associated with declining but not healthy macadamia trees, supporting the previous suggestion that sudden death of macadamia trees is primarily caused by girdling of trunks resulting from infection by fungal pathogens.
KEYWORD Macadamia integrifolia; Nectria rugulosa; Phytoplasma; Quick decline; Xylaria arbuscula;
ARTICLE INFO Botanical Bulletin of Academia Sinica, Volume 39 Number 4 October 1998, page 251-254, 4 pages
PUBLISHER Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China