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Poster: Diseases of Plants: New & Emerging Diseases


New canker disease of Incense-cedar in Oregon caused by Phaeobotryon cupressi
J. WEILAND (1), R. Sniezko (2), M. Wiseman (3), M. Serdani (3), M. Putnam (3) (1) USDA-ARS, Horticultural Crops Research Laboratory, U.S.A.; (2) USDA Forest Service, Dorena Genetic Resource Center, U.S.A.; (3) Oregon State University, Botany and Plant Pat

Incense-cedar (Calocedrus decurrens) is a tree native to Oregon and California. Since the early 2000’s, a canker disease has been observed with increasing frequency on ornamental and windbreak trees planted in the Willamette Valley of Oregon. Symptoms appear as dead, flagging, small-diameter (<1 cm) branches that are scattered throughout the crown. Phaeobotryon cupressi was consistently isolated from symptomatic trees located along the length of the Willamette Valley. Identification was based on morphology and on sequences from the internal transcribed spacer (ITS) and the translation elongation factor 1-α (EF1-α) region. Six isolates were tested for pathogenicity on potted 0.6-1 m tall incense-cedar saplings. Approximately 1 to 1.5 months after inoculation, inoculated branches began to turn brown and die, while control branches that received no inoculum remained healthy. P. cupressi was described as a new species in 2009, and was originally found causing cankers on Italian cypress (Cupressus sempervirens) in Iran. The pathogen was also detected once in the U.S. from Juniperus squamosus in Kansas. It is unknown whether P. cupressi affects native stands of incense-cedar, where similar symptoms have been observed, but studies are underway to evaluate the extent of this disease in Oregon.