Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1915-04-23
THE RHIzOCTONIA
A Recently Recognized Disease Whieh
Causes Considerable Damage==how i,
Recognize and Something About lii
Treatment

Orono. Me-. April 20.-Potato grow
ers, and even those who are particular
ly interested and concerned with po-
tato diseases, when they observe
stunted or otherwise abnormal plant
are apt to speculate as to the cause OF
the difficulty rather than to search for
it below ground. Weak, abnormal or
missing plants are often accounted for
as due to weak Seed weak eyes,
improper use Of fertilizers, etc.
whereas a careful examination of the
parts below ground, particularly early
in the season may give the matter an
entirely different aspect in the mind
Of the interested party. Certain stud
les made by the plant pathologists of
the Maine Agricultural Experiment
Station would seem to indicate that
what is known as the Rhizoctonia dis
ease is frequently responsible for con-
ditions like this in certain parts Of
Maine.
Unfortunately, no satisfactory COM
mon rame has been suggested for this
trouble. The term ''Rhizoctonia"
comes from the name Of the fungus
which has been found to be constantly
associated with the diseased condition
in Maine. For years this fungus has
been known to be particularly common
in New England potato soils. and in
this section of the country has been
looked upon as Of no economic import
&c of mid ).
distribution in the United States. Dur
ing the past summer the pathologist
Of this Station had an opportunity to
examine potato fields in a dozen diff
ferent states from Maine to California.
Many different fields were examined in
each state, and on very few Of these
did he fail to find the fungus after a
five or ten minutes search, in many
instances producing disease Often the
injury to the plant was such as to ma
terially reduce the yield of the field.
This was particularly the case in one
noted potato section of California.
The fungus has long been known to
be intimately associated with the po-
tato even in New England. Its occur
renee on the potato tuber is familiar
to every housewife or others who have
occasion to prepare potatoes for the
table. The small brown or black close
ly adhering spots of dirt which won't
rub off are not dirt at all, but the
Overwhelming stage of the RhiZocto-
MIA fungus,-simply compact masses of
the fungus threads. The fungus does
practically no harm here so far as real
injury is concerned, but it does its real
damage in the summer when both it
and the potatoes are growing. On the
potato tubers it is sometimes called
black scurf.''
Investigations carried on by this
Station show that veal. and uneven
stands of some years may be due fire.
Quently, although not always, to the
attacks of the Rhizoctonia fungus. A
potato seed piece may be strong and
vigorous, and start to put out sprouts
in q normal way. but soon these begin
to show dark brown patches of vari-
Gus sizes, on their surfaces, often the
whole sprout being affected and killed
Again smaller diseased areas may en-
tirely encirc!e the stem, and also cause
its death before it reaches the surface
of the ground These dark brown
areas are invariably found to be COW
cred by the Rhizoctonia fungus.
Certain fields have been observed at
the time the plants We're five to eight
inches high, and have been covered up
once or twice, where quite a percent
age Of the plants were apparently I'M