Gail Ruhl, Senior Plant Disease
Diagnostician, Purdue University
pathogen found in state for the first time at Portage store -
IN Department of Natural Resources Press Release - July 31,
Guide and Checklist for Identification of Sudden Oak Death (pdf
file) - includes sample submission criteria for Indiana - Purdue
(aka Sudden Oak Death) Wanted Poster (pdf file)
List of Regulated Hosts and Plants Associated with Phytophthora
ramorum (pdf file) - as of August 2013
Click here to
view a past What's Hot article on Sudden Oak Death
Phytophthora ramorum is the fungus like
micro-organism that causes Ramorum blight and sudden oak death
first identified in 1993 in Germany and The Netherlands on ornamental
ramorum was isolated in June 2000 from dying trees in California.
Since its discovery in North America, P. ramorum has
been confirmed in forests in California and Oregon and in nurseries
in California, Oregon, Washington and British Columbia. There
are programs addressing Phytophthora ramorum in forests
settings and in production nurseries.
The disease can produce rapid decline in tanoak (Lithocarpus
densiflorus) and in susceptible species of oak (Quercus),
characterized by bleeding cankers on the lower trunk of trees.
These cankers produce a sticky, very reddish substance. Mortality
appears less likely with other plant species. Damage from SOD
in Rhododendron, Vaccinium ovatum and Arbutus
menziesii typically involves leaf spotting, cankers on
small branches and stems, and/or stem dieback.
The spread of SOD likely occurs through infected plant material,
rainwater, and soil. Foliar hosts may play an important role
in the transmission of P. ramorum to bark canker hosts.
Moist, cool, windy conditions are thought to spread the pathogen
by dispersing spores from the leaves of foliar hosts.
At present, the entire host range of this pathogen
is unknown. However,
Phytophthora ramorum does naturally infect and kill
or injure at least 43
host species (pdf file) and has been recovered
from an additional 54 plant species.
Although many species of Phytophthora are considered common or
in Indiana, P. ramorum is NOT one of them.
On July 31st,
2006, Phytophthora ramorum was reported by Dr.
Robert Waltz, IDNR Director of the Division of Entomology and
Plant Pathology to have been confirmed by the U.S. Department
of Agriculture Animal and Plant Health Inspection Service,
Quarantine (USDA APHIS PPQ) on a sample submitted from a Viburnum
(a common shrub) located in the garden
section of a hardware store in Portage, Indiana. The infected
sample was shipped to the
store from an
The plants have been removed from the site and buried deep in
per USDA APHIS PPQ protocols.
The introduction of this pathogen to Indiana is a cause for concern,
goal is to
keep this disease from becoming established in our Indiana landscapes
forests, and the best way to achieve this goal is to educate
about this disease.
Due to P. ramorum's broad host range and non-descript
symptoms, trees and
shrubs infected with the pathogen are difficult to distinguish
with other diseases. Use the checklist provided
on this website to
help determine if a sample should be submitted for further evaluation.
more information on Sudden Oak Death, please see our links below.
Government Links/Regulatory Info
State Detection Plans for Phythophthora ramorum
Consult the North Central IPM Center’s
Web site at http://www.ncipmc.org/alerts/suddenoakdeath/index.cfm for
examples of existing state Phythophthora ramorum detection
plans for homeowner plants, as well as some helpful Web resources.