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


The Alfalfa WeeviI {
prepared by the United States Departments
Of Agriculture.)
Farmers in regions newly infested
by the alfalfa weevil will be interest
ed in knowing that an unusually ef-
fective method Of control has been
worked out by the United States De-
partment of Agriculture. Specialists
Of the department say that rarely has
any method Of insect control been SO
thoroughly safeguarded against, fail
Ure as alfalfa-weevil spraying. 1t has
been tested every season for seven
years. The cost of the operation
about 81 an acre-is trifling compared
with the returns, and no farmer in the
territory infested or threatened can
afford to overlook 1t, the specialists
say. There Is no control measure,
however, which can be applied advan-
tageously this late in the season. Eff
fective work must be delayed until
next spring.
Control by Poison Spray.
Control is effective by spraying poi
son over the fields so that it will cover
the growing parts on which the
weevils mostly feed. Arsenate of lead
and arsenite Of zinc have been mostly
used, but other arsenicals recommend
ed for orchard spraying are thought
to be about as good. There is practi-
cally no danger of burning the foliage
of alfalfa, and therefore the range of
suitable poisons is larger than in fruit
tree spraying. Arsenate Of lead Is
said to be, everything considered, the
best poison to use, principally because
it sticks to the leaves more readily and
costs less than most of the others.
The poison is weighed or measured
at the rate of two pounds Of powder
OF four pounds of commercial paste
for each 100 gallons Of water. Is
stirred with q little water in pail
Jumps, is diluted and strained into the
sprayer tank. Two pounds of laun-
dry soap for each, gallon should be
added, In order to make the liquid
stick to the leaves properly. The
dry, powdered form of the poison Is
better than the paste. There Is no
danger of stock being poisoned by hay
cut from sprayed fields where the pol
son is applied at rate of not greater
than 100 gallons of spray mixture per
acre.
Simple Outfit Sufficient.
The essentials Of the spraying outfit
are: A truck or other vehicle, tank
with an agftator to keep the poison
from settling to the bottom, q pump, q
pressure gauge, an engine and pump
ing jack, unless the pump is to be
driven by hand, strainer, a pipe for
distributing the liquid from the pump,
and as many nozzles as are required
by the capacity of the pump. These
essentials may all be contained In
barrel-pump outfit carried in g wagon.
The pump must be capable of deliv-
ering four-fifths of a gallon or more
q minute and maintaining pressure
of at least 70 pounds. If the pressure
is less than that, the mist spray will
not be fine enough to prevent the
liquid from. gathering In drops and
running to the ground instead Of dry
ing on the tops Of the plants.
The number of nozzles used should
be sufficient to take up the capacity
of the pump. At the average walk
ing gait of team, each nozzle should
deliver nine -tenths Of gallon a min
ute. Therefore, q pump of nine-gal-
Ion capacity per minute will supply
ten nozzles, each Of which covers q
strip two feet wide. By an arithmet-
ical calculation Of the cubical con-
tent of the pump cylinder ana the
number of strokes per minute, the ca
pacity of the outfit can be determined.
The spray should be applied at the
rate of 100 gallons Of spray mixture
per acre.
Nearly any kind Of spraying outfit
can be adopted for this purpose. How
ever, modern orchard spray outfits are
usually designed to give comprehen-
sively small flow and high pressure,
and are less suitable for alfalfa
spraying than the older pumps. with
larger cylinders and longer strokes,
designed for larger flow and lower
pressure.
The spraying outfit should be mount
ed on the wagon or other vehicle used
so that the nozzles will be about two
feet above the tops of the alfalfa
plants. Four 50-gallon barrels with
an engine and pump mounted on an
ordinary wagon, or. for hand-pump |
outfit, an express wagon and fewer
barrels constitute satisfactory out |
fit. 4 paddle, dasher, or some other
form oY agitator must be provided to
keep the liquid stirred. A strainer of
2O-mesh brass or bronze screen should
be fitted to the opening through which
the water enters the tank and an
other over the outlet leading to the
pump. The parts Of the pump in which
close fitting Is required should be OF
brass, bronze, porcelain, or some other
substance less rapidly corroded by the
chemicals than iron and steel. All
commercial spray pumps are built in
this way, but pumps which were in
Feeding Young Stock.