Northern Wisconsin advertiser. [volume] (Wabeno, Wis.) 1898-1925, 1906-05-10

The potato industry In Wisconsin is
handicapped by three important
enemies the early blight, the late
practical problems concerning the ION
troll OF these three enemies.
First, what is early blight? The term
blight is often very broadly used
among the potato growers, even to the
extent of calling an early whitening of
the vines blight. Early blight proper
is caused by semi-parasitic fungus,
macrosporium solani. 1t seldom at
tacks the healthy vine directly, but
gains entrance after the vine has be-
come weakened by injury Hence its
prevalence during seasons OF seri-
Gus damageg from the beetle. The APP
pearance OF yellow leaves and dark
circular spots upon the foliage in
dicates the early presence of the dis
ease.
Under favorable conditions this
appearance may develop to the extent
of giving the entire field a speckled
and blackened appearance The stalks
turn yellow, grow spindly, and ripen
prematurely several days in advance
OF the season. During unfavorable
seasons for fungus development, the
disease may exist unobserved during
the period of most active growth, and
later multiply rapidly at the expense
of the forming tubers. A microscopic
examination at this stage will show
the presence of thousands Of club
shaped conidia in the tissues OF the
plant. The name EARLY Blight is
misleading because its effects may be
most noticeable during the months of
August and September. IL must be
remembered also that the fungous
does not attack the tubers directly,
but the yield results in an inferior
grade OF potatoes. with high per-
centage OF culls.
Quite in contrast to early blight,
late blight is caused by an active.
virulent. parasitic (Phytopthora In
festans). The disease is a native of
the wild potato vine OF South Ameri-
ca and was introduced into Europe,
early In the 10Th century. In 1845
II swept over Germany and the Brit
ish Isles as an epidemic, causing
practically the loss OF the entire crop.
Due to its economic importance In
these countries, the life history OF the
fungous, as far as 1t Is known, was
early worked out by German and
English horticu,turists and scientists.
The greatest advance toward the con-
troll Of the disease has been made in
this country in recent years, due In
part to the production OF efficient
spraying machinery, suitable for
large commercial plantations.
Moist. warm weather during the
months OF August and September is
especially favorable for the develop
ment OF the late blight fungus. Under
these conditions, In two days time.
the disease may turn an apparently
healthy field into mass of patrefied
and blackened vines. A most un-
fortunate feature of the disease is that
IL not only destroys the vines. but
the summer spores may gain entrance
TO the tubers and cause serious dam
age from rot. The rotting of potatoes
in storage. which is very generally
attributed TO the late blight fungous. is
very likely due to bacterial causes.
The relative Importance OF the early
and late blight fungous TO the Wiscon-
sin potato industry is not definitely de-
termined. The loss from early blight
is more steady and it is probable the
do afreA
every season. Late blight appears
more periodically, but when it Is
present causes more serious damage
to the yield
The success Of any commercial
spraying venture depends upon the
efficiency of the selected fungicide in
controlling the disease and upon the
actual increase in profit. which can
be realized above the cost of treat.
ment In New York state several po-
tato growers are cooperating with
the experiment station to determine
the profits under actual farm condi-
lions. A report of that work for 1906
estimates the cost of each application
at 90 cents per acre. They obtained
an average increase OF IS bushels per
acre, which netted s22 per acre. Later
reports indicate that potato spraying
has made rapid progress in that state
and is becoming quite general among
the progressive growers.
Probably no spraying consideration
OF the horticulturist or gardener car
be accomplished as rapidly. as cheaply
and as efficiently as can potato spray
ing. The machines have reached /,
high grade of perfection. making J.
possible for two men and one team
TO cover thoroughly about % acres II
one day. Also, combining poison
with Bordeaux mixture not only facil
itates in controlling the bugs, bu
also divides the cost between the TIVE
treatments.
One Of the results OF the potato
spraying agitation viii be the intro
duction OF better methods in fightin:
the beetle. Serious loss resulted il
the state last year, due to the clums,
and careless methods of applyin.