Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1917-07-19
POTATO BLIGHT APPEARS.
Agricultural Extension Service Of State
University Issues Warning.

University Issues Warning.
The weather conditions Of the past
week have been very favorable to the de-
velopment of the late blight Of the pota-
to. A careful examination by the Agricul-
tural Extension Service Of the State Uni
versity of potato plants from plots in
Burlington has shown the disease on some
of the leaves. The disease appears as ir-
regular dead. shrivelled, brown spots on
the edges or sides Of the lower leaves
especially those leaves in contact with
the soil. The weather conditions at Bur-
lington (high temperature and humidity
have probably been fairly general
throughout the State. A general late
blight infection is therefore to be feared.
and growers Of potatoes. whether on city
lots or in fields are warned of the dan
ger to their crop unless spraying with
Bordeau mixture Is carried out as soon
as possible.
TREATMENT.
The spray mixture-No better compound
has been discovered with which to combat
potato diseases than homemade Bor-
deaux mixture. 1t is made of copper sui
phate (blue vitroD. water slaked lime
and water. 1t is only fungicide and does
not kill the Colorado potato beetle. II
combined with Paris green or arsenate Of
lead. both insect and fungus are attack
cd. Paris green Is quicker In its action
than arsenate Of lead. but washes off more
readily and is more costly. Either works
we'll. Both adhere to the foliage much
longer II applied In connection with the
Bordeaux mixture. The spray mixture
should be made as follows: Dissolve 80
pounds copper sulphate In 30 gallons OF
water In a wooden vessel by suspending
the crystals In a sack over night. Slak
80 pounds of lime with water and add
enough more to make 30 gallons. These
are the stock solutions. They may be pre-
pared at the beginning OF the season and
Will keep indefinitely. but must not be
mixed until the day they are to be used
On the day the spraying is to be done. put
| three gallons Of the blue Wtriol solution
In separate container and dilute this to
approximately 20 gallons. Put three gal
Ions OF the lime solution in another con-
tainer and dilute this to 20 gallons. Then
mix the two solutions. stirring rapidly as
they are poured together. The mixture
should be strained through sack OF
piece of cheesecloth to remove the lime
particles. Stir three quarter pounds OF
Paris green Tor one and one-half pounds
dry arsenate of lead) in a little water un'
III II forms paste and add II to eacf
barrel of the mixture. Then add watei
enough to bring the whole to 80 gallons
Time OF application-The first application
should be made when the newly hatchec
potato bugs" are seen or the flower
buIs appear, usually the first week ir
'uly. The foliage. especially the lowel
leaves should be thoroughly covered. 9th
er applications should be made at inter
vals OF about two weeks. An application
about September l is especially desirable
since late blight epidemics at this time
are usually followed by destructive po
tato rots.
Cost of materials-Two barrels to thu
acre should be used. costing: Three
pounds Of copper sulphate q lSc. $40; on
and one-half pounds of Paris green q b5'
~; three pounds Of lime q 1c. Sc; one ap'
plication, $40; four applications $S'0''
The results-Bordeaux arsenical spray
ing. IL properly conducted, insures I'M
crop against blight and beetles. No bani
should loan money on potatoes that arr
not thus cared for. The protection agains
early death from tip-burn and flea-oeeti'
injury will repay the cost Of the spray
Ing In years when no blight OCCURS