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The INDEPENDENT, January 21, 2010
Can You Dig It?
By Schann Nelson
OSU Master Gardener
I was sure for awhile that my front yard
had been taken over by a giant growth, that
I was no long standing, or driving, or walk-
ing or working in DIRT but that it was all one
giant FUNGUS. The hard freeze tamed the
giant ‘fungus among us’ but perhaps that’s
the motivation for the following detailed
tirade.
I’ve been disappointed for several years
in our potatoes, in our garden and in the
stores. I don’t like losing half of every tuber to scab and/or dry-
ness. Frankly, if you can find a good potato, that’s the best part!
With a wee bit of research, I found, among many familiar photos
of scabby potatoes, the delightfully named silver scurf. The stealth
bomber (complete with sexy name) of potato diseases, silver scurf
is caused by the fungus Helminthosporium solani and is not read-
ily apparent at harvest, but causes its damage in storage. Lesions
first appear as small brown spots that merge together on the sur-
face, dry out and slough off in storage. Mature lesions have defi-
nite edges and are named for their silvery appearance when wet.
Losing the outer layer causes the tuber to shrivel and dry out un-
til there isn’t much left to eat.
Science experiment: Place a potato in a plastic bag containing
moist paper towels. Seal the bag, punch a couple of small holes
in the bag, and store the bag in the dark at 60 to 75 degrees F for
two to three weeks. Do not allow the tuber to dry out. After two to
three weeks you should be able to see fruiting bodies that are de-
scribed as looking like Christmas trees, but I think they look more
like the thick moss on maples, tiny, branchy stems. If you’re buy-
ing a bunch of seed for commercial production, this is one test you
can do.
One of the coolest things about this fungus (besides the name)
is that control is primarily cultural and physical intervention. It
turns out, the cost/benefit analysis for fungicides usually works in
favor of the fungi. It’s more a matter of deciding what your level of
tolerance for damage is, rather than getting ‘rid’ of the fungus.
Fungicides are available although the post-harvest application of
fungicides is no longer recommended. The disease is adept at de-
veloping resistant strains. General biocides (such as ozone or
Learn how to identify and control
Garlic Mustard, an invasive weed
Coming Soon to a Wood-
lands Near You! Invasive Garlic
Mustard. This is the kickoff for
a Women Owning Woodlands
Network (WOWnet) group for
Columbia/Washington/West-
Multnomah Counties.
All are welcome on Satur-
day, February 6, from 12:30
p.m. to 3:30 p.m. at 11275 NW
Skyline Blvd, Portland.
The afternoon will start with
a brown bag lunch, introduc-
tions, and talk about what sorts
of things WOWnet would like to
accomplish through the forma-
tion of a local network. Then
learn how to identify and con-
trol garlic mustard, one of the
area’s newest and nastiest
woodland invaders. Sen Sper-
off, a woodland owner on Sky-
line Ridge, will share her ex-
pertise in combatting this inva-
sive weed with all of who at-
tend. Then the group will be go-
ing into the woods to get up
close and personal with garlic
mustard and discuss the most
effective strategies for dealing
with it.
Bring a sack lunch, water
bottle, sturdy shoes, rain gear if
appropriate, and gloves.
Added bonus: That morning,
from 10:00 a.m. to noon, there
will be a free weed workshop in
the same location hosted by
West Multnomah Soil and Wa-
ter Conservation District. Learn
about many other weeds, in-
cluding ivy, knotweed, holly,
blackberry, etc. and learn how
to use a variety of tools to com-
bat them.
For more information, go to
www.wmswcd.org
chlorine dioxide), biological products such as Bacillus subtilus and
Pseudomanas syringae, and clove oil showed little effect on the
development of the disease in storage. Soil treatment of fungicide
prior to harvest does not appear to affect disease incidence.
Fungicide can be used on seed crops, in addition to strict sanita-
tion, temperature and humidity control over the long season of
storage. It does appear that highly infected seed yield a higher
rate of infection in daughter potatoes.
The good news and the bad news is that the disease is seed
borne, but does not survive well in soil. Chances of infection from
the soil are greatly reduced after two years without potatoes. This
is the kind of nit-picky detail that can drive the home gardener
crazy. Trying to rotate crops through the same ten garden beds is
a challenge. Since infection occurs as soon as tubers begin to
form, when conidia (spores) enter the periderm (skin) of the devel-
oping tuber, ruthless elimination of volunteer potatoes in spring is
critical. I’m also going to worry less about the peels that go in the
compost.
A sample crop rotation, beginning the year following harvest:
one year of zealous extermination out from under a leafy crop,
maybe cucumbers; a second year crop of legumes (free from po-
tato volunteers or you have to start over); a third year (hopefully
the second volunteer-free year) of brasicas; until finally, no less
than three years after harvest, I could plant potatoes in that soil
again. By this time investing in high quality seed potatoes, possi-
bly even fungicide treated seed, looks like a much better invest-
ment!
Management requires an integrated multi-tactic approach:
• Use seed that is free or relatively free of silver scurf.
• Harvest potatoes as soon as skins are set. Infection continues
and increases over the season, even after vine death and is often
not detectable at harvest.
• Maintain healthy growth until shortly before harvest. This
means not allowing the vines underneath to die back prematurely.
• Store potatoes carefully (dry, dark and cold-but-not-freezing).
Storage facilities should be steam and detergent washed to disin-
fect, dry and free from straw, dirt and debris.
• Practice crop rotation with at least two years between potato
crops.
Go forth into the rain, the wind, the weather and find the struc-
ture underneath the slime!
OSU offering Basic
Forestry Shortcourse
The OSU Extension Service
will be offering the Basic
Forestry Shortcourse begin-
ning February 10th in St. He-
lens. This six-session class is a
great introduction to planning,
growing, and caring for a small
woodland. Tree and shrub
identification, planting and
maintenance, fish and wildlife,
tax and business basics, har-
vesting and marketing and oth-
er topics will be covered.
Registration deadline is Jan-
uary 25 and space is limited.
For more information, contact
the OSU Extension Service,
503-397-3462.
Special Events?
Club Meetings?
Attendance is important for
successful events and meet-
ings, whether they are large or
small, social or civic. Whether
you are in Vernonia, Banks,
Mist, Buxton, Birkenfeld, Elsie,
Jewell or Timber, you can
reach more people with an arti-
cle in The INDEPENDENT.
You can send the informa-
tion by mail to: 725 Bridge
Street, Vernonia, OR 97064, or
by email to: rebecca@the-in-
dependent.net
If you prefer an eye-catching
ad that won’t cost you an arm
and a leg, call The INDEPEN-
DENT at 503-429-9410.
Church Directory
N EHALEM V ALLEY B IBLE C HURCH
S EVENTH D AY A DVENTIST
F IRST B APTIST C HURCH
Gary Taylor, Pastor
Grant & North Streets, Vernonia
503 429-5378
Sunday School 10:00 a.m.
Morning Worship 11:00 a.m.
Nursery available
Wednesday Service 7:00 p.m.
Gary S. Walter, Pastor
2nd Ave. and Nehalem St., Vernonia
503 429-8301
Morning Worship, 11:00 a.m.
Sabbath School 9:30 a.m.
359 “A” Street, Vernonia
503 429-4027
Sunday School 9:45 a.m.
Sunday Worship Service 11:00 a.m.
Wednesday Prayer Meeting 7:00 p.m.
A SSEMBLY OF G OD
S T . M ARY ' S C ATHOLIC C HURCH
Wayne and Maureene Marr
662 Jefferson Ave., Vernonia,
503 429-0373
Sunday School 9:45 a.m.
Morning Worship 11:00 a.m
Rev. Luan Tran, Administrator
960 Missouri Avenue, Vernonia
503 429-8841
Mass Sunday 12:00 Noon
Religious Educ. Sunday 10:30 a.m.
V ERNONIA C HRISTIAN C HURCH
V ERNONIA C OMMUNITY C HURCH
Sam Hough, Minister
410 North Street, Vernonia
503 429-6522
Sunday School 9:45 a.m.
Sunday Worship 11:00 a.m.
(meets in Youth & Family Center)
Home Group Meeting
throughout the week
at various locations
Grant Williams, Pastor
957 State Avenue, Vernonia
503 429-6790
Sunday Breakfast 9:00 a.m.
Morning Worship 9:45 a.m.
Children and Nursery 10:00 a.m.
Youth Group 6:00 p.m.
Preschool Mon. & Wed. 9:00 a.m.
Wednesday Prayer 6:00 p.m.
Tues. & Fri. Adult Volleyball 7:00 p.m.
V ERNONIA F OURSQUARE C HURCH
Carl Pense, Pastor
850 Madison Avenue, Vernonia
503 429-1103
Sunday Worship Service: 10:30 a.m.
Children’s Sunday School
C HURCH OF J ESUS C HRIST
OF L ATTER D AY S AINTS
Marc Farmer, Branch President
1350 E. Knott Street, Vernonia
503 429-7151
Sacrament Meeting, Sunday 10 a.m.
Sunday School & Primary 11:20 a.m.
Relief Society, Priesthood and
Young Women, Sunday 12:10 p.m.