Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1892-08-19

For Potato Growers.
The Difference between True Blight and
the "New Disease" Explained.

The Difference between True Blight and
the "New Disease" Explained.
STATE AGRICULTURAL
EXPERIMENT STATION,
BURLINGTON, VI, Aug II, 1892.
Editor Of The Phgnir:
The true blight or rust has appeared on
the potato leaves, and the weather is favor
able for the rapid and destructive spread
of the disease Unless preventive meas
ures are taken at once there will be much
loss from the rot. Those who intend to
use the Bordeaux mixture should not de-
lay an hour longer than is necessary.
Since sending you my former letter, two
weeks ago, a large number of letters of in
| quiry have been received which emphazse
the need of further information by the
farmer as to the so called ''new disease" of
/ the potato. This disease has attacked
early potatoes very generally throughout
the state 1t is an entirely different and
| distinct disease from the true blight and it
is very important that all potato growers
learn to distinguish the two maladies. A
circular which it is hoped will aid them in
so doing has been sent to the postmasters
throughout the state for free distribution
The most important practical differences
between the diseases noted in this circular
are as follows:
1st The spores of the fungus which
causes the true blight or crust" pass from
the blighting vines to the tubers causing
the rot. No rotting of the tubers is caus-
ed by the new disease.
I'd. The true blight or rust attacks
later potatoes worst. The new disease
is confined to early potatoes.
Sd. The true blight or trust" can be
checked by spraying with the Bordeaux
mixture. The new disease is not so easily
checked by spraying.
The following points will aid in distin-
gushing the two diseases:
New disease: Practically everything in
the way of diseased potato leaves up to
this date, Aug. l., has been the 'new dis
ease This is everywhere on early pota-
toes, so far as we can learn. The diseased
plants appear sickly and of a yellowish
cast instead of dark, healthy green
Soon leaves turn yellow and die. The
death begins OH uninjured leaves about the
tip and edges, and the leaves die rather
slowly, so that they become crisp and cur
at the tip and edges as the disease pro
crosses. The trouble is worst on leave,
. that have been partially eaten by potato
bugs or other insects Whenever the lea
is injured the disease attacks it and spread,
, from these spots. Thus leaf may show
a score or more of black spots varying il
J size from pin head to marble. In SOM
pieces of early potatoes every leaf is deat
or dying.
Blight: Very few potato growers will
mistake the true blight or rust whel
they see it. This disease is commencing L
t show on later potatoes The large blush
< black spots appear on the leaves at an
place. The disease spreads so rapidly tina
the whole leaf is killed in a day or two
4 There is not time for it to dry and cur
but it hangs limp and rotting from tn
n stem. The surest evidence of the bligh
as distinguished from the new disease
e the presence of the mildew which cause
= the blight 1t can easily be seen on tn
p under side of the rapidly blighting leave
r. as a delicate white mildew which looks lik
e frost work upon or about the edges of III
5 black spots.
IL L Il JoNFs RotaDist