16 Summer 2017 Applegater
GRAPE TALK
Red grape leaves are
pretty but…
BY DEBBIE TOLLEFSON
As a rural realtor, I often show vineyard
properties for sale in the Applegate Valley.
Late last summer while walking with a
buyer, I noticed beautiful red leaves on
some of the vines. I thought the leaves were
especially pretty with their unusual red
veins. A few weeks later, though, I learned
about grapevine red blotch-associated virus
(GRBaV).
Vaughn Walton, an associate professor
of horticultural entomology at Oregon
State University (OSU)-Oregon Wine
Research Institute in Corvallis, leads
a research program on the biology of
horticultural insect pests, especially those
associated with grapevines. He has worked
with thrips, leafhoppers, treehoppers,
mealybugs, rust mites, phylloxera (a species
of lice that preys on vines), and stinkbugs
in vineyards. Dr. Walton’s lab was the first
to record the spread of grapevine leafroll
and red blotch viruses in Oregon.
The red blotch virus is one of over 60
different viruses identified in grapevines
since the 1960s. It was already prevalent
in California when it was first observed
in Oregon in 2009. Red blotch differs
from most grapevine-infecting viruses in
that it has DNA (deoxyribonucleic acid)
rather than RNA (ribonucleic acid), so
identification depends on genomic tools.
DNA testing of a specimen from the
early 1940s at University of California,
Davis, proved the presence of red blotch
girdling
About one week after girdling,
the leaf or cane will change color.
Lomakatsi partnering on Upper
Applegate Road Demonstration Project
BY SHANE JIMERFIELD
The Applegate watershed hosts an
amazing diversity of wildlife habitat, forest
types, and recreation opportunities. It
provides clean drinking water to homes
and businesses and water for irrigating
farms and orchards. But a changing
climate and decades of fire suppression
Vaughn Walton, associate professor
of horticultural entomology
at OSU-Oregon Wine
Research Institute, Corvallis.
veins often change to pink or red. Red
blotch can affect both mature and new leaf
plantings. The disease can be confirmed
only through DNA-based analysis, since
visual diagnosis can be complicated by the
multiple viruses that could be infecting
the vines and by the fact that a vine with
no symptoms can often test positive for
the virus.
Richard Hilton, entomologist at
Southern Oregon Research and Extension
treehopper
Treehopper adult feeding on cane,
causing girdling.
in Sonoma County decades ago. The virus
is moving very slowly in the Willamette
Valley, but is spreading quickly in southern
Oregon and the Applegate Valley. So far it
has not been reported in vineyards outside
North America.
Like leafroll disease, red blotch causes
a reddening of the basil leaf margins from
late August through September. Unlike
leaves affected by leafroll, however, the red-
blotch leaf stays relatively flat and the green
are threatening its ecosystems and human
communities that depend on the forest for
their quality of life and clean water.
Lomakatsi is a nonprofit ecological
restoration, education, and training
organization. For more than 22 years, it
has worked across the region in partnership
Center (SOREC),
OSU’s extension
service in Jackson
County, says, “The
identity, biology,
Debbie Tollefson
and management
of potential red blotch vectors is currently
a major topic of research at SOREC.”
These and other scientists are studying
the causes of this new virus, the vectors
spreading it, and the effects of the disease
on grapes and the wines produced from
those grapes. Effects include reduced
yields, reduced sugar content, delayed
fruit ripening, reduced production weight,
elevated acidity, diminished color, and
altered tannins.
Using infected scion and rootstock
in grafting can spread the disease. Other
factors could be insect vectors, including
suckers like leafhoppers and treehoppers,
drought and other environmental stresses,
soil conditions, and fungal pathogens.
Vineyard owners need to be sure they
are using scion and rootstock that have
been tested with a DNA-based molecular
test. Treating plants for treehoppers, the
most likely vector, may help prevent
further infestation and slow down the
spread of red blotch.
It’s not just vineyard owners who should
be grateful to the work being done to
identify the vectors that spread this disease
and to find a solution for it. Because red
blotch virus affects grape quality, valley
economics, and, ultimately, the taste of our
wines, we should all be grateful!
Debbie Tollefson
debbie.avrealty@gmail.com
Quady North viognier is Editor’s Choice
Quady North 2015 Steelhead Run Vineyard Viognier is Editor’s Choice and received
93 points in Wine Enthusiast’s June 2017 Buying Guide. Also listed are Quady North
2015 Eevee’s Vineyard Grenache Blanc (91 points), Quady North 2013 Mae’s Vineyard
Syrah (91 points), and Plaisance Ranch 2014 Carmenère (90 points).
with agencies, communities, schools, tribes,
organizations, and private property owners
to restore ecosystems and increase the
sustainability of ecosystems, communities,
cultures, and economies.
Lomakatsi is excited to again partner
with the US Forest Service (USFS), the
Bureau of Land Management, and the
Nature Conservancy to bring its extensive
individual and collective experience
in ecological forest restoration to the
Upper Applegate Road Demonstration
Project. The project will demonstrate four
treatment alternatives in close proximity
to each other so that scientists and the
public can evaluate the results of different
treatment types. (See article by Don
Boucher in the spring 2017 Applegater.)
The partnership has been seeking
community participation in the project,
including offering public tours of the sites
to increase knowledge of the project.
This spring Lomakatsi’s forestry
t e c h n i c i a n s h a ve b e e n p re p a r i n g
demonstration sites for treatment, marking
trees to be removed on all four treatment
sites. Although none of the treatment
alternatives has a timber focus, small-
diameter trees will be removed as a
by-product of restoration effort. Sale
of these small-diameter logs will help
fund additional restoration work. This
commercial timber harvesting is scheduled
for May through July and will utilize
a helicopter for yarding. Although a
helicopter is expensive to use, helicopters
provide the lightest touch on the land, a
high priority to Lomakatsi. Minimizing
on-the-ground impacts to vegetation
and soil is important ecologically and
significant to the evaluation of results.
Working with USFS, Lomakatsi’s
technicians and inspectors will oversee the
In fall 2016, community members and
representatives from the Applegate
Neighborhood Network, Applegate Trails
Association, US Forest Service, The Nature
Conservancy, and Lomakatsi reviewed the
project sites and discussed the project’s
design and objectives.
project, supervising contractors to ensure
they are meeting treatment specifications
and following guidelines. Lomakatsi
will periodically monitor project sites to
measure and compare the effectiveness of
the different treatment types.
In the fall, Lomakatsi’s technicians and
restoration saw crew will be completing the
treatment prescriptions by carrying out
noncommercial thinning. When thinning
activities are completed (anticipated in
November), Lomakatsi will offer a public
tour to review the immediate outcomes.
Slash pile burning should be completed
within two years.
Project partners and community
members are hopeful that this collaborative
process can be carried forward into a larger
community-supported project over the
next few years in the Upper Applegate
Watershed. Learn more about that project
on page 13 of this Applegater.
Shane Jimerfield
Program Director
Lomakatsi Restoration Project
shane@lomakatsi.org
