le in all spraying.
In the case of leaf-eating insects, this means covering every leaf
with the poison and applying it to the under side of the leaves,
where the insects generally feed. In the case of sucking insects,
thoroughness means an effort to touch every insect with the spray.
It should be borne in mind that the insect can be killed only when
hit with the chemical. The solution should be well stirred, and
should be applied by means of a nozzle that will coat every leaf
with a fine, mist-like spray. Mere drenching or too prolonged an
application will cause the solution to run off. Special precautions
should be taken with contact poisons to see that the formula is
correct. Too strong a solution will burn the foliage and tender
bark.

Spraying apparatus: There are various forms of spraying apparatus in the
market, including small knapsack pumps, barrel hand-pumps, and
gasolene and gas-power sprayers, Figs. 97 and 98. Hose and nozzles
are essential accessories. One-half inch, three-ply hose of the best
quality is necessary to stand the heavy pressure and wear. Two
50-foot lengths is the usual quantity required for use with a barrel
hand-pump. Each line of hose should be supplied with a bamboo pole
10 feet long, having a brass tube passed through it to carry the
nozzle. The Vermorel nozzle is the best type to use. The cost of a
barrel outfit, including two lines of hose, nozzles and truck,
should be from $30 to $40. Power sprayers cost from $150 to $300 or
more.

Spraying material:
_Arsenate of lead_ should be used in the proportion Of 4 pounds of the
chemical to 50 gallons of water. A brand of arsenate of lead
containing at least 14 per cent of arsenic oxide with not more than
50 per cent of water should be insisted upon. This spray may be used
successfully against caterpillars and other leaf-eating insects in
the spring or summer.

_Whale-oil soap_ should be used at the rate of 11/2 pounds of the soap
to 1 gallon of hot water, if applied to the tree in winter. As a
spray in summer, use 1 pound of the soap to 5 gallons of water. This
treatment is useful for most sucking insects.

_Lime-sulfur wash_ is an excellent material to use against sucking
insects, such as the San Jose scale and other armored scales. The
application of a lime-sulfur wash when put on during the dormant