The San Juan islander. [volume] (Friday Harbor, Wash.) 1898-1914, 1913-06-06
FARM AMP :!.!.i' ORCHARD
from Agcln0a 1olo and Experiment Stations
Of reoon and Washington Specially Suitable Pacific Coax Conditions
Watermelon Wilt Is
Hard to Control.

Watermelon Wilt Is
Hard to Control
Oregon Agricultural College, Cor
vallis-W Watermelon wilt, destructive
in some parts of Oregon, is fungous
disease causing great loss where 1t oc
ours, as, once established in field, II
lives there for years and kills off the
plants whenever watermelons are
planted there.
F. D. Bailey, of the crop pest force
of the Oregon Agricultural College
Experiment station, has done consider
able work with this disease. 1t is
generally distributed, he says,
throughout the southeastern part OF
the United States, and has been re-
ported from Iowa, Indiana, Arizona,
Oklahoma and California.
"The name indicates the character
istic symptom, the willing and droop'
ing of the foliage, which comes on
suddenly and in short time the plant
is Dead" says Mr.. Bailey. "Some-
times a pinkish, mold-like growth
comes out on the surface of the stem
soon after the plant is killed, extend
ing for a foot or more up the stem
from the crown.
"This wilt is caused by fungus cap
able of living in the soil for several
years, and that may attack any melon
plants afterwards planted in such
fields. This fungus lis composed of a
very delicate branching thread-like
growth, so delicate its presence could
not be detected in the soil. On COM
ing in contact with the tender roots
of the melon plant, it penetrates, and
once within the tissues it finds the
proper nourishment for rapid growth.
Very small spores are produced and
set free in the vessels, where they
terminate to start new points of in
lection. Having terminated they pro-
duce a growth which plugs up the YES
sells and so prevents sap flow. This
results in wilt and the death of the
plant. Often the fungus comes to the
surface, where another and larger kind
of spore may be produced in great
numbers and readily carried by winds
or insects, thus helping to scatter the
disease over wide areas.
''This disease is frequently spread
to new fields through the application
of manure. Diseased plants frequently
are carried to the compost heap. 1t is
also claimed that the fungus spores
are not killed when passing through
the alimentary canal of cattle, so that
it is necessary to avoid any chance for
cattle to pasture on wilted vines.
SIN the first place, every precaution
should be taken to keep the disease
from spreading to new fields. Tools
used in field where the disease is
found should be cleaned and sterilized
before using them in ground free from
the trouble. Do not drive or walk
directly from the one to the other, or
allow soil to be transferred, as it
might be where irrigation is practiced.
Keep the compost heap free from the
fungus. When the disease appears in
a patch, the plants affected should be
removed and burned as soon as dis
covered.
s'In districts where this wilt is al
ready widespread and the future cult
walton of melons is desirable, the only
course is to secure resistant strain
by breeding and selecting. This has
already been done in several localities
in the Southeast, and work is in pro-
gress toward this end at one place in
the Willamette valley. 1t has been
found that these resistant strains can
rarely be transferred to new locations
and still retain their resistance. The
problem, therefore, becomes an individ-
ual one for each localitp.
"The experimental work consists in
crossing the watermelon with the
citron, which is more hardy and re-
sistant to the wilt. By following the
breeding with careful selection re-
sistant melon having good flavor and
shipping qualities can be developed
The details of the work necessary
can be obtained by writing to the de.
partment of plant pathology of the
agricultural college.