Bugs, Cicadas, Aphids, and Scale-insects 189 
blackish narrow elongate curved scale, resembling a little an oyster-shell 
in miniature; this is the sometimes serious apple-pest, Mytilaspis pomorum. 
But we have no space to list 
even the most important of 
these degenerate but successful 
insect enemies of our fruit- and 
foliage-trees. 
The devising of remedies for 
scale attack has been given much 
attention, and a number of effec¬ 
tive means have been discovered 
for fighting the pests. Probably 
the most effective of all is the 
fumigation of infested orchard- 
trees by hydrocyanic gas. A 
tent capable of enclosing a whole 
tree is made, and with this in 
place hydrocyanic gas is gen¬ 
erated under it by pouring 
about 50 oz. of water into 5 oz. 
of commercial sulphuric acid and 
dropping in 15 oz. of cyanide of potassium, these amounts of acid, water, and 
cyanide being sufficient to fumigate a tree 12 ft. high by 10 ft. in foliage diam¬ 
eter; that is, to fumigate about 1000 cu. ft. of space. For larger or smaller trees 
change the amounts of acid, water, and cyanide proportionally. Of washes 
to be applied in winter, when the leaves are off, the best is one made of lime 
50 lbs., sulphur 50 lbs., salt 50 lbs., water 150 gals.; slake the lime with 
water enough to do it thoroughly, and during the process add the sulphur. 
Boil one hour with water enough to prevent burning and until the mixture 
becomes of a deep amber color. Dissolve the salt in water enough to do 
it quickly and add slowly to the boiling mass. When all is thoroughly 
mixed together and has actually boiled at least an hour add water enough 
to make up 150 gals., and apply by spraying or washing while hot. It 
may be safely applied when the foliage is off to any fruit-tree, garden shrub, 
or small fruit, and is a very effective “ scale-killer.” Of sprays for the leaves, 
crude petroleum and kerosene emulsion are the best. For use, undiluted 
crude petroleum should be entirely untreated and of specific gravity of 43 0 
or over on the Beaume scale. Smith has used this oil safely on all ordinary 
fruit-trees, but advises not applying it to peach-trees. At time of apply¬ 
ing, the trees should be dry, the oil of a temperature not below 6o° Fahrenheit, 
and the nozzles should throw a perpetual fine spray. Kerosene emulsion is 
made by boiling J lb. of hard soap in 1 gal. of water and then adding 2 gals. 
Fig. 257.—The red orange-scale, Aspidiotus 
aurantii. a, females, natural size, on leaf; b, 
female, much enlarged, removed from under 
waxen scale; c, the scale, composed of wax 
and exuviae, much enlarged; d, just hatched 
young, much enlarged; e, male, much enlarged. 
(After Jordan and Kellogg.) 
