THE EUROPEAN ELM SCALE IN THE WEST. tt 
A more satisfactory method of control is the use of miscible oil 
containing 23° to 28° Baumé oil, which can be obtained from dealers 
under various trade names. This should be used in the following 
proportions: 
Miscible oil (23° to 28° Baumé) ____ ____ 1 gallon or 16 gallons. 
AO NTE lla SR age i ae Se 12 gallons or 184 gallons. 
It is mixed by first pouring the requisite amount of oil into the 
spray bucket, barrel, or tank to be used and then adding a small 
amount of water. With considerable agitation this will become light- 
colored and of a creamy consistency, whereupon more water may be 
added, and finally all the water, in the meantime agitating thor- 
oughly. This may then be applied with any sort of spray outfit, 
providing the apparatus has power enough to send a spray to the 
tree tops. 
The bucket or barrel pump will do very well for small trees, the 
ordinary orchard power outfit for trees up to 40 feet in height, and a 
high-power apparatus for trees above this height. (Fig. 6.) <A 
pump registering a pressure of at least 800 pounds with a capacity 
of 12 to 15 gallons or more per minute is necessary to reach trees 60 
to 90 feet high, which is often the height of mature elms. A spray 
gun or solid-stream Worthley nozzle is necessary to force the spray 
to the tops of the trees from the ground. The use of a smaller outfit 
and ladders is not to be recommended, on account of extra cost and 
unsatisfactory results. 
Large trees require from 30 to 50 gallons of mixture, costing from 
3 to 4 cents per diluted gallon for the material and 14 to 24 cents per 
gallon to apply it. 
Every branch and twig should be covered, but too much spray 
should not be allowed to settle about the base of the tree, as it might 
injure the roots. No damage to elm trees or lawns has been noted, 
however. 
The spraying should be done in the winter up to the time the 
buds begin to open in the spring. Probably a weaker spray could 
be used on the young forms in the late summer but this would be 
about as expensive, for nearly twice the amount of material would 
be required to cover each tree on account of the foliage, and it 
would be much less satisfactory since all parts, particularly the 
underside of the leaves, which are the most heavily infested, could 
not be thoroughly covered. 
If properly done, spraying should not be necessary every year, 
except upon young trees, which seem to become reinfested easily 
when near unsprayed large trees. Extermination, of course, is not 
to be hoped for, but it is possible to kill a sufficiently high percent- 
age of the insects to prevent their appearance in large numbers the 
following season. 
SUMMARY. 
The European elm scale was introduced into this country about 
1884 from Europe and was first found at Rye, N. Y. From there 
it has spread until it is now located in 27 States and the District of 
Columbia. Although more widespread in the East, the injury to 
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