The Prince George's enquirer and southern Maryland advertiser., 1922-07-07

tended for other purposes should be
reftted when used for spraying.
An engine-driven outfit must have
relief valve near the pump, permit
ting the surplus flow to return to the
tank. The pump must have an air
pressure chamber large enough to
keep the flow steady and insure even
distribution of the poison. Even pres
sure, indispensable for uniform spread
of the poison, cannot be maintained
without pressure gauge. This
gauge should be attached to the pres
sure chamber OF near 1t and at dis
tance from relief-valve and nozzles.
The boom or pipe which carries the
nozzles and supplies them with liquid
from the pump is made Of two-fo0t
pieces Of one-half inch galvanized iron
pipe joined by Us, each Of which af-
fords an opening for the attachment
of nozzle. The boom is connected
with the pump by a one-half inch
pressure hose. The boom should be
supported by piece of timber, two by
four, clamped or hinged to the truck
with the boom stapled, bOlted, or
wired to it. Plain misty nozzles,
without strainers or other complies
tions, should be used.
Spray in Warm Weather.
The best time for spraying is at
what the specialists call the turning
point of weevil nfestation--from one
to two weeks before the first crop is
ready for cutting, when the young
larvae become so numerous that they
completely destroy the growing tips.
After that point is reached the
weevils, If left alone, consume the
leaves until nothing Is left but the
woody fibers. If spraying is done
at this time the crop RECEIVERS quick
ly. Spraying yearly in the spring
sometimes entirely prevents damage,
but it is uncertain. On the other hand,
plants sprayed after they were en-
tirely stripped of their foliage have
been able to recover and bloom, but
this allows destruction to go too far
and makes recovery too slow.
Spraying at the turning point" not
only protects the first crop but con-
fers an even larger benefit on the sec
ond crop, which sprouts and grows
without delay, and no treatment OF
the stubble Is necessary.
Stubble spraying, after the cutting
of the first crop, has been successfully
done, but it requires getting into the
field Immediately after cutting and
mu0h larger quantity Of liquid is re-
quired than if it were applied to the
first crop. Stubble spraying, there
fore. Is advised only when earlier
spraying has been impossible.
Spraying should be done, If possible,
at the beginning of warm spell. The
weevils do not feed so voraciously in
cool weather, and if the poison is ap-
piled at the beginning Of a cool spell
it may become largely impotent before
the weevils resume feeding freely.
When spraying Is done under favor
able weather conditions most of the
weevils are killed within four or five
days.
There : are other control measures,
but none Of them promises much more
unless applied before or Immediately
after the first cutting. One method Is
to pasture the alfalfa field until most
Of the eggs and young larvae have
been destroyed. Another Is to use
the alfalfa as soiling crop, cutting
it green two or three times during the
season. These methods, however,
must be practiced before the turning
point of infestation, as after that time
the weevils destroy the plants so COM
pletely that there is not enough growth
for either pasture or soiling. Another
method Is to cultivate the field with
a harrow or other implement, imme-
diately after the first cutting, in such
way as to cover the field with dust
mulch, thus exposing the entire sur
face of the field to the sun and kill
ing most of the weevils. In some in
stances, the second crop has been pro-
tected by dragging the stubble, while
it is still wet from irrigation. with
the land leveler or the clod breaker.
This causes the insects to perish by
embedding them in the mud, but it Is
harmful to the soil and is not recon-
mended.