Cheyenne record., 1920-03-04
] TREAT DISEASE
IOF ONION PLANT
Smut Works Overtime IN Trying
b Snuff Out Young Seedlings
by Forming Blisters.
FUNGUS CAUSE Of AILMElT

ceetrei Of Trouble 10 Accomplished BY
changing Location ef bed 70
Clean soii-AIso Plant ssts
Instead o. Ssed.
prspared BY the unit.a states Depart
ment Of Agriculture.)
Maybe 1t Is because of its strong
small. Anyway there II some mag
netlc attraction which apparently
draws disease Of various kinds and
conditions to the onion crop. Take,
tor Instance. onion smut. It works
overtime In trying to snuff out the
young seedlings by forming brownish
black. elongated blisters which finally
split the leaves and expose the pow
dery black mass Of spores within the
interior Of the blister. A specific
fungus causes this onion ailment, the
spores wintering in the ground and
again attacking the young seedlings in
the spring.
The onion is susceptible to the fun
gus only while in the young Seeding
stage. After the plants reach Z height
Of three to four inches they become
immune to further infection. Smut
spreads slowly In the soil, but an
infested area in neld 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
Of onion sets should use caution that
they do not contaminate the soil by
planting smutted sets.
Control is accomplished 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 10
per cent formaldehyde solution II used
with each gallon of water. this diluted
solution being applied at the rnte Of
200 gallons per aero or ! gallod to 1876
feet of row. Farmers bulletin No.
1850. recently issued BY the United
0t1tcS pdHt11cAta " sh8IAS4tA01ySsN = W.
scribes in detail the apparatus used i'm
applying this fungss destroying seed
protector. AS rule, It costs about
IS m acre to insure the onion crop
against smut losses in this manner. It
is advised that the tops OF diseased
onions bs burned after harvest In or
der to prevent the return Of injected
onion refuse to the soil. The spread
ing Of waste from onion warehouses L.
bad practice. is p fsaaTssse.. !. =; ~ &
A Destructive Plant pIssass. q
Onion mildew or blight IT, ssome-
times serious In the cooler and more
humid onion districts. + The diseass
commonly starts IN the held IN spots;
and spreads to the surrounding areas,
its development being greatly aided by
moist weather. It centralixes it, 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
ducCICu lC0NCS OShnk DEuuChCS OA 0AC
fungus, which bear abundant spores.
Warm weather promotes spOre ger
mination. 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
1t decreases the moisture in the air
near the surface Of the soil. Good
air drainage Of the fields 10 also es-
sential so that excessive dew and fog
may be avoided. Rosin fish-oil soap,
as a sticker, makes the use of bor-
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 fish-on
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. ei 'f,a,A
Onion leaf mold is a disease Of
minor Importance except in Louisiana
and California, where 1t occasionally
causes large losses. It occurs in
mid-season and causes the tips Of the
leaves to die back. No satisfactory
control has been perfected. t,lT'.
striek attention to sanitary meas
ures and careful sorting Of diseased