Sunbury American and Shamokin journal. [volume] (Sunbury, Northumberland Co., Pa.) 1840-1848, 1845-08-16
Potatoe Blight.

10 THE EDIroR OF THE TRIBuNE,--k now.
ing that you feel deep interest in the welfare
of the farmer send you few observations on
the cause OF the disease among potatoes, so pie.
valent last year, which think have discover
ed, and perhaps remedy.
This morning for the first time, I observed
few top. of the poatoe. in my garden beginning
to wther and curl up. Surprising that the cause
might be near at hand commenced critical
examination of several wthered tops. to disco
ver i. if possible soon found green fly a,
bout one fourth Of an inch IN length, upon eve.
~ top that had begun to wlther, and on ,nost Of
them two some had four, few six. On ono
top found four young flies nbont one halft tho
size of the adult, and on three Others one each,
about one fourth grown.
This insect, | Thought. must be :he cause of
the disease, commonly called the Curl-Top or
Potato Rot, since found it on every diseased
top in 30 or 40 cases. and usually on the part of
the plant which had begun to wither near the
healthy part of The stem. On the stem Of one
| where the fly was there was small globue Of
viscd transparent liquid. This stem had be.
gun to droop, but only so little that it would
scarcely be observed. Another globule on the
upper side of a curled leaf on which fy was
sitting, was found TO be sweet. Many of the
leaves that were much wilted felt is ii a rluti-
nous liquid had been spread upon the upper SUR
face. These questions then, naturally arose:
( Does this liquid exrda from the plant and
attract the fly which is innocently slipping his
; nectar or does he perforate the stein md canSe
toe exudaton. that like malicious parasite he
may extract the lie from this root ltapprurs
+ to me that the insect must be the cause Of the
eXudaton, FOR the reason, that it was on no plant
that did not have the fly upon it.
/ In almost every case two flies were found up
on the same plant, differing little in size and
color, the less being ofa darker green, and the
large containing many eggs, winch it appeared
to be deposiiirg. Only one egr was found in
the stem of the plant; yet there were many p'a-
ces apparently stnng upon the diseased stem,
and the effect of this reached dorn in somn ca,
ses three or four inches in the heart Of thu strm
others followed down as far as the healthy rar..
; FROM lnc 0nONc UDStrNhtlOuS 'u'sH C1lCih'
sions appear to be evident. that the Sting Of this
fy causes the curl.top-that it breeds upon the
stem and the numerous progeny live upon The
plant, sucking up i's juices AMI destroying ',s
vitality. As rcmCda | amputrtcG the diseased
part and destroyed all the flies could. About
10 o'clock sprnkled soapsuds upon one small
patch and none were found uHon il at night,
though many were found upon another piece
that was not shuwered. An lronr before sun
set sptnked the suds left from washing upon
the whole.
The flies can perhaps be driven out of the
field with a bush where it is not convenient I'd
shower them. Yours, &c, l.. H.
PoMrty, n. y July II, lSl5.
p s. Tuesday morning another examination
was made and only one fly was to he found on
the piece.