28 
ough wetting difficult in summer, or with scale insects which are so 
irregular in the time of disclosing their young that many summer 
treatments would be necessary to secure anywhere near complete ex- 
termination. In the winter also, with deciduous trees, very much less 
liquid is required, and the spraying may be much more expeditiously 
and thoroughly done. In the case of badly infested trees, a vigorous 
pruning is advisable as a preliminary to treatment. 
DUSTING AND SPRAYING APPARATUS. 
POWDER DISTRIBUTERS. 
For the application of powders the dusting bags already described 
(pp. 11-12) are very satisfactory for field work. Much more expen- 
sive and more rapid 
machine distributers 
have been devised, but 
these are rarely used. 
For garden work 
some of the small 
powder bellows and 
blowers are excellent. 
These cost from $2 
to $8. 
LIQUID SPRAYERS. 
For the application 
of poisons in liquid 
form the prime essen- 
tial is an apparatus 
which will break up 
the liquid into a fine 
mist-like spray that 
will coat every leaf 
and every other part 
of the plant as lightly as is compatible with thoroughness. The 
essential features of such an apparatus are the force pump, suitable 
hose, and nozzles or spray tips. The leading pump manufacturers 
now put out a large variety of spraying apparatus suited for all 
ordinary needs, including the small knapsack pumps, barrel and tank 
pumps, and geared and power sprayers. For limited indoor opera- 
tions a hand atomizer or even a sprinkling can with fine rose tip 
may be made to do fair service. 
127 






I'ic. 3.—Barrel spray pump. (From Waite.) 

