Montpelier examiner. [volume] (Montpelier, Idaho) 1895-1937, 1920-03-05
Smut Works Overtime in Trying
to Snuff Out Young Seedlings
! by Forming BIisters.
FUNGUS CAUSE OF AILMEN1
control Of Trouble Is Accomplished by
managing Location Of Bed to
Clean soiI-AIso Plant Sets
Instead Of Seed.


netic attraction which annaraptiv
draws disease of various kinds and
conditions to the onion crop. Take.
Tor instance, onion smut. II works
overtime in trying to snuff out the
young seedlings by forming brownish
oiack. elongated blisters which finally
split the leaves and expose the pow-
derry black mass of spores within the
interior of the blister. A specifi.
Fungus causes this onion ailment, the
spores wintering In the ground and
again attacking the young seedlings in
the spring.
me onion is susceptible to the fun
gus only while in the young Seeding
stage. After the plants reach a height
OF three to four inches they become
immune to further infection. Smut
spreads slowly in the soil, but an
infested area in O field will gradually
become larger and more severely dis
eased each year onions are grown on
such an area. The spores are spread
on farm implements, the feet of men
and animals, by surface water and In
dust carried by the air. Purchasers
or onion sets should use caution that
they do not contaminate the soil by
planting smutted sets.
Control is accomplish In home gar.
dens by changing the location Of the
onion bed to clean soil, or by planting
sets instead of seed. In large COM
mercial onion districts of the northern
states fOrmaldehyde solution is ap-
piled In the furrow with the seed, as
this disinfectant holds the fungus in
check. One fluid ounce of 81 to 40
per cent formaldehyde solution is used
with each gallon of water. this diluted
solution being applied at the rate of
2OO gallons per acre or ! gallon to 1S5
feet of row. Farmers bulletin No.
1O6O recently issued by the United
States department Of agriculture. de-
scribes in detail the apparatus used In
applying this fungus-destroying seed
protector. AS rule, IT costs about
50 an acre to insure the onion crop
against smut losses In this manner. It
is advised that the tops OF diseased
onions be burned after harvest In or
der to prevent the return Of infected
onion refuse to the soil. The spread
ing of waste from onion warehouses is
a bad practice.
A Destructive Plant Disease.
Onion mildew or blight is some
times serious in the cooler and more
humid onion districts. The disease
commonly starts In the field IN spots
and spreads to the surrounding areas,
its development being greatly aided by
moist weather. 1t centralizes its at
tack on the leaves, which turn yellow.
become covered with furry growth,
and eventually collapse. The disease
occurs wherever onions are grown ex-
tensively. although the control varies
In different sections. A fungus causes
the disease, the furry masses on the
affected leaves being branches of the
fungus, which bear abundant spores.
Warm weather promotes spore ger
miDatiOn, and hence is favorable to
the spread of the disease.
As the spores winter in the onion
field, an efficient crop rotation is one
commendable method of control, the
supplementary growing of cabbages.
potatoes. and sugar beets with onions
being valuable. Good soil drainage
also helps to reduce the blight. since
It decreases the moisture In the air
near the surface Of the soil. Good
air drainage Of the fields is also es-
sential so that excessive dew and fog
may be avoided. RosIn flsh-oil soap
as a sticker, makes the use Of Dor
deaux mixture effective In controlling
onion mildew. The bordeaux mix
ture consists of four pounds Of cop
per sulphate. four pounds Of quick
lime, three pounds Of rosin ish-oil
soap, mixed with water to make a so
gallon solution. Complete directions
for making this spray are furnished
In the department Of agriculture bull
letin.
Onion leaf mold Is a disease Of
minor importance except In Louisiana
and California, where II occasionally
causes large losses. II occurs I'm
and causes the tips Of the
leaves to die back. No satisfactory
control has been perfected.
Strict attention to sanitary meas
ures and careful sorting Of diseased
bulbs at harvest time are the chief
means of controlling Fusarium rot.
which reduces the roots to a mass
Of white moldy growth.
Onion smudge. confined largely TO
the white varieties, results In o
smudgy. undghtIy appearance Of the |
bulbs and an ultimate reduction In !
the market quality Of the crop. As
the disease is dependent largely on
abundant moisture, special care is nee
essary in handling the white varieties
The crSp should be harvested quickly.
avoiding any exposure to rain II pos
sible. They should be stacked In an
open shed and allowed to cure thor
oughIy. The white sets should be