Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1889-08-03
Potato BLIGHT.

Mr.. Roland Thsxter of the Connecticut
experiment station, has Published the follow
ing bulletin on very important subject.
and one Of special interest 10 the farmers Of
Maine. where the potato is 50 largely grown
1t 10 hardly necessary to call the attention
Of farmers 10 Ceaneesicuf 10 the prevalence
of the 90 called potsao blight. which In some
localities in the State threatens to render the
crop total failure should the prevailing
damp weather continue. a. least xs far ~
concerns the late varieties Since tn true
nature Of the blight is COMMONLY misapPre-
hendsd by farmers the present note may be
Of interest in view Of the alarming rspadity
With which the disease spread within the past
fortnight
The potato blight result, from the attack
Of parasitic fungus (PaytophthO,a tnfss-
tans) which, within the potato leaf. pro
iuees threzdIike growth, which, during
moist weather. extends itself rapidly and ap-
pears externally on the other side in the form
Of whitish bloom or mlidsv that NAY be
easily seen With the naked eye about the
edges of the shrivelied. biacken<d portions
Of the leaf which the fungus has already de-
stroyed. This whitish bloom consists of
numerous threads which bear countless num-
bers Of the - els or .poses Of the fungus
which are blown about among the potato
plants and serve to spread the disease with
great rapidity. Having lighted upon the
leaves when moist With dev or rain, they
germinsEe either by sending out threadlike
growth. which penetrates directly into the
| leaf. or by the production of what are called
zoospores. This latter method serves TO
multiply the means Of conta gion still further,
since each fungus spore may emit as many
u
mobile bodies much like aniinalcules in Ap
pearance, which after making their exit from
! the fungus spore, swarm about for a while,
finally coming to rest, each zoospore germi-
mates by sending out threadlike growth,
which penetrates the leaf and spreads within
it. We may thus have as many as fifteen
ne~ points Of infection arising from single
| fungus spore.
| This fact serves to explain the extraordl-
nay rapidity with which the disease has
spread during the past two or three weeks.
/ and also suggests mode of checking the
spread of the fungus when il has not gone
too far. II is not possible 10 cure leaf that
has the fungus already inside it, but we can
| prevent the spores from entering new leaves
| by applying substances which prevent ger
minatlon. The best mixture for this pur-
pose which experience has shown to be of
value in treatio. this disease, is the Boz
deaux mixture, which is being tested BY the
experiment station on an experimental plot
| Of potatoes. The proportions used are as
follows Sulphate Of copper ten pounds,
dissolve in two gallons of hot water; lime,
fresh unslaked. ten pounds, siake in three
gallons of water: pour the copper solution
into wooden barrel or tub and add water,
twenty-five gallons. Then pour the lime
| ,,,; yfu Viii hsa
the copper solution slowly, and stir the whole
rapidly while so doing. 1t is sometimes
safer to let the lime mixture cool before
adding il to the copper solution but this is
not necessary il it is added slowly and thor
oughly stirred. The two concentrated solu-
tons of copper and Of lime should never be
poured together while hot Always dilute
the copper solution as allowed described be-
fore adding the slaked lime. The lime must
be fresh otherwise the mixture may burn the
leaves When prepared as above directed,
the leaves will be wholly uninjured by the
application
In applying the mixture a brass force
pump and fine spray nozzle should be used
which will cover the foiae well without
drenching it, The Bordeaux mixture should
be allowed to stand at least over night before
using, and should be strained through fine
copper RanZe TO AVOID cl0yglhg tne nozzle
A piece Of such gauze tackled over the bot
tom Of a berry box will answer; but in strain
ing the mixture it should he poured onto the
gauze slowly, from a height Of two feet, and
can thus be made to run directly through
without clogging
The application should be made if possible
Immediately after a rain, and should be re-
peated after it has Washed off. 1t is, how
ever very alhprent to the leaves and does
not wash off readily. When potatoes are
very badly attacked no treatment will save
them, and in such CAGES they should be dug
and marketed as soon as possible since the
fungus penetrates the tubers as well as the
foliage and causes them to rot. When the
leaves have shown signs of the blight it is
never safe to try to winter the potatoes
When of two fields one is blighted and the
other free from blight, it is advisable to
avoid walking through the unblighted field
after having walked through the blighted one
since the spores may be readily carried and
disseminated in this way.