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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #327007
Title: New canker disease of Incense-cedar in Oregon caused by Phaeobotryon cupressi.

Author
item Weiland, Gerald - Jerry
item SNIEZKO, RICHARD - Us Forest Service (FS)
item PUTNAM, MELODIE - Oregon State University
item WISEMAN, MICHELLE - Oregon State University
item SERDANI, MARYNA - Oregon State University

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Incense-cedar (Calocedrus decurrens) is a native tree occurring in Oregon and California. Since the early 2000’s, a new 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 (200 km). Identification was based on morphology and on sequences from the internal transcribed spacer (ITS) and the translation elongation factor 1-a (EF1-a) region. Six isolates were tested for pathogenicity on potted 0.6-1 m tall incense-cedar saplings in an outdoor canyard. Approximately 1 to 1.5 months after inoculation, inoculated branches began to turn brown and die, while negative control branches 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 native range in the western U.S.