The Morris County chronicle. [volume] (Morristown, N.J.) 1877-1915, 1903-08-21
POTATO BLIGHT AND ROT.
Spraying Tested as n Remedy at the
Vermont Experiment station.
fro BE Continued

| Spraying Tested as "a Remedy at the
Vermont Experiment station.
A single application of bordeaux par
is green mixture to potatoes at the Yer
mont experiment station protected the
plants somewhat against insect attacks
in 1901, but was no protection against
the late blight and rot.
In a trial Of paris green alone, as
compared with bordeaux paris green
mixture, little was demonstrated en-
cept that the proper use of bordeaux
mixturS sn potatoes is a very profita-
bic operation In many cases, however,
the work is only half done. 1t is then
of little value.
In regard to results from spraying
last season the station authorities say:
Little is to be added to what has been
stated heretofore. Bordeaux mixture
again proved a reliable remedy in a
trying season. The twice sprayed rows
appeared almost as green as those
sprayed three times More rot appear
ed in those twice sprayed than the con-
dition of the tops led us to expect The
loss was probably due in part to the
fact that the two earlier sprayings
were made by unskilled farm laborers,
who gave less attention than our train
ed assistants usually do to spraying the
lower leaves. The fungus, therefore,
had an opportunity to develop suff1-
GENTLY on these to cause considerable
rot except on the plot where the third
and more careful spraying was made
AS a matter of fact we believe that If
the second spraying had been made as
thoroughly on the lower leaves as was
the first 1t would have sufficed to pre-
vent the rot that occurred
Spraying the Soil For Rot.
There are various causes for the rot
ting of potatoes. The common one in
Vermont is the invasion of the tuber
by the same fungus (phytophthora)
which causes the late blight or rust
of the leaves. The popular idea of
those who have observed this associa-
ton of the blight and the rot is that
the fungus causing the disease passes
down the stem, but De Barry advocated
some forty years ago that the decay Of
the tuber results chiefly, If not wholly,
from the spores which fall from the
leaves to the soil, and this explanation
has been accepted by the later bota-
nists generally. While carrying on our
spraying experiments last summer it
occurred to us to try the effect of
spraying the soil underneath the plants
in certain unsprayed rows where the
blight was developing. 1t seemed prob
able that If the rot of the tubers re-
suits from spores falling upon the soil
such spraying would reduce the
amount Accordingly, early in August
nine rows were set apart for this trial
The soil was a gravelly loan, fairly
well drained, variety Delaware, plant
ed May 10. The plants had not been
sprayed up to this time, and there was
a sprinkling of blight evident on the
foliage of many of them, and, as the
results show, the spraying was delayed
too late for the full protection of any
Of the plants.
The results are not to be interpreted
finally, but so far as they show any
thing 1t is that spraying the surface of
the soil greatly reduced the amount Of
rot This result is in harmony with
the idea that tuber infection results
from spores passing through the soil
This method is not advocated as a
practical remedy.