The Delawarean., 1900-05-23
THE DESTRUCTIVE PEA LOUISE.

( of the largest pea-canning factories in
America, with a capacity of $4,000
cans per day is located ait Seaford, and
in 1898 this and half dozen smaller
plants located at Bridgeville, Harring-
ton Houston, Milford and Milton,
packed some 144,00O cases of two
dozen cans each-the crop of over
1000 acres.
During the season OF 1899 a serious
blow was given this usually profitable
industry by the appearance of a small
plant louise upon tlle peas in such
countless numbers as to cause AN all
most entire loss to the late crop and
from one-half to two-thirds of the
usual yield of the earlier sorts. These
small insects, which closely resemble
the green fly of greenhouses and the
wheat aphis" ON wheat, except that
they are considerably larger and en-
tirely of light pea green color, com
menced to appear about the time the
early peas were in blossom.
These small insects injure the plant
by sucking its juices and thus more or
less depicting its vitality. Though the
few present at first did hardly any
damage, they soon multiplied so ran
idly, that the plants were entirely
coated with them. AS a consequence
the vines soon died or very imperfectly
matured the peas. With the cutting
OF the pea crop these insects were not
noticed further except here and there
in garden patches where they might
be found until late in November.
The question most naturally arises
at once, Where We're these lice before
they appeared on the peas in the
spring or, in other words, where and in
what State do they pass the winter?"
Were it known that the pea louise
passed the winter upon a given weed
or crop means might be devised for SO
handling it as to prevent it's spread to
the peas Unfortunately, last spring
the lice were not noticed until we'll
along in May, and in the fall nothing
of a definite nature was ascertained as
to their winter habits. This year dur
ing the last month, however, the Sta
tion Etomologist has been examining
various crops in the vicinity of pea
fields to ascertain whether they might
not harbor this pest, and especially
those crops which are in the ground
over winter.
Only within the last week has he
found the louise to be excessively nu-
merous ON crimson clover, and Though
most abundant in the southern portion
of the State, and especially near the
pea fields SO badly infested last season,
the lice have been found very numer-
GUS as far north as Dover and not un-
common in New Castle county. AIT
Bridgeville the lice are still almost
entirely confined to the clover, upon
which they occurred in larger numbers
than at any other point which has been
visited, and hardly any were found on
peas adjoining the clover. At Har-
rington the lice were found rapidly adj
vancing across one pea field next to
clover and quite generally scattered in
another large plot.
There seems to be but little doubht.
therefore, that throughout Delaware
most of the pea lice have spent the
winter on the scarlet clover and hav-
ing reproduced so rapidly as to have
become excessively abundant upon It'll
they are spreading to the peas Only
the winged forms will spread to the
peas, upon which they will deposit
young, which will each mature and re-
produce 25 to 80 young in from a week
to ten days, and these winged lice are
very largely spread by the wind.
1t has been ascertained that the pea
louise, with which as such we were un-
familiar previous to 1899, is undoubted-
ly the same as louise noticed for five
or six years past upon scarlet clover.
This was probably the same insect
which appeared in such numbers on
scarlet clover few years ago. In one
or two instances. 1t then threatened
the life of the crop,but was very quickly
and almost entirely exterminated by a
fungous disease. But few diseased lice
have been found this year, and though
the clover furnishes peculiarly favor
able conditions for the development of
this disease, it is doubtful if many lice
upon the peas will Ibe killed by it.
If the scarlet clover in the immediate
vicinity of peas can be turned under
deeply at once commencing upon the
side nearest the peas-without doubt
most of the lice will be destroyed, as
they could never regain the surface, and
their otherwise Subsequent spread
would be prevented. Where the clover
is desired for forage or seed, this may
not seem feasible. 1t may be worthy
of consideration in some cases, how
ever, whether it were better to en-
danger the pea crop by leaving the
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