The suburban citizen., 1900-07-21
WAR ON INSECT PESTS.
A WAY OF RENDERING PLANTS
BAAEFUL TO THEIR ENEMIES.

,
tural Science and the Association of
Economic Entomologists, that plants
may be so cultivated as TO change their
chemical constitution, rendering them
either agreeable or baneful to insect
pests, yet without injury to the
plants themselves. suggests the large
possibilities OF scientific agriculture.
And this, one is told, is no mere the
Dry, but a demonstrated fact. A to-
baccO grower, whose name was not
given, has already put this in prac-
tice. He analyses his plants and finds
which are nutritious and which are
not so to the insects; and he Cultivates
those that will starve out the insect.
His method seems to depend largely
in the mature and experienced judg
ment Of the grower, varying according
to circumstances. Professor Galloway
suggests the extension of similar
methods to starve out those other
pests. now so destructive, the Hessian
fly in wheat. and the aphid in
pea plants. which, for lack Of a bet
ter name has been called the green
pea louise, and which has almost
ruined the cror in Maryland for two
years-the Neciarol lhora destructor
One of the ost instructive papers
read was that o', Professor Johnson on
! the ravages Of this insect and the
fight against it. A small, weak, harm
less-looking creature, it came down
on the pea plants in May, 1899 blight
as silent and as sudden almost as the
destruction of Sennacherib's army.
Whole fields turned black and per-
! ished. causing the loss of half the
crop. or S3,O00,O00, and this year
| S4.OO0.OO0. The insect is viviporous;
some are winged, some wingless, but
all females and parthenogenetic Be
! ginning to breed when eleven days
old. they have six to twelve young
daily for nearly month, so that tax
ing the minimum number, over 100000
will be produced from one in six
weeks. The young are oXtruded feet
first, "born kickcTs," and IL is several
minutes before the head appears, dur
ing which time they exercise their
feet constantly AS soon rs born they
attach themselves to the leaf. ana
remain for two days immoyable, suck
ing the Juice of the plant, which is
converted into a sort of honey dew
sticky and tarry, ruinous to clothing
and even to shoes of persons who go
through the fields. SO numerous are
they as sometimes to cover the leaf
entirely. A bushpl of them is shaken
down from a row of peas ten rods long.
Spraying was at first practlced to
kill them, but this killed also their
enemies. Now the system is to plant
peas in rows, and to shake off the in
sects and follow with a cultiyator,
buryng them when they die within
two days, and on the third day the
process is repeated.
Their most efficient enemy is the
larva of the Surplus, which deyours
them at the rate of one Il minute, but
these in turn have their enemies. Bas-
sus is a parasite on them. Other in
sects also prey on the aphids; and GER
tain parasites attack them. A fungus
disease, Empusa, has proved very de-
structive. Their original habitat
seems to have been clover, from which
last year they emigrated to neighbor-
ing pea-felds, with such destructive
results. Professor Johnson stated
and others in discussion confirmed the
statement, that this insect has ap-
peared in destructive numbers this
year at many places. Professor Web
ster reports their appearance partlc-
ularly in Ohio. 1t is feared that other
regions will share the rate Of Mary
land However, the belief was eX-
pressed by several members that the
insect may disappear as rapidly as it
came. Instances in point are not lack
ing. Professor Hopkins a few years
ago noted the outbreak of n destruct-
i've insect among the evergreen trees
Of West Virginia, which has now ut
terly disappeared.
The question Of nomenclature Of in
sects as regards the common names
was brought up by criticism by Pro
fessor Fletcher, Of the name Of green
pea louse," applied to this insect as
| it is not louse at all. but an aphid,
! and there is no such plant as green
pea; simply the peas are used when
| green; also, the insect thrives on ether
plants, and it's usual habitat is clover.
Many other anomalies exist in the
name commonly applied to insects,
very different names being applied TO
| the same insect in different localities.
On the other hand, different insects
are designated by the same name,
causing great confusion. Professor
LOunsberry instanced the oyster-shell
! scale. This resembles the oyster
shells of this country, but not those
Of South Africa, so the name seems
inapplicable to the same scale there.
An amusing instance Of multiplication
of names was mentioned in the case
Of the harlequin cabbage bug, which
is also called in Maryland the firebug,
because it destroys vegetation as If a
fire had swept over the country; also
the Catholic bug, because it has a
cross on its back, and the Spanish bug
because it has the Spanish colors; four