88 Farmers’ Bulletin 1169. 
Habits —Nothing unusual is known as regards the habits of these 
insects, so that a reference to any of the other aphids discussed in this 
bulletin will give an adequate idea on this subject. 
Remedies.—Kerosene emulsion (p. 12-13) or 40 per cent nicotine 
sulphate (p. 13), applied when the aphids are observed, will give 
necessary relief. 
WOOLLY ELM BARK APHIS.” 
How injurious—The vitality of trees is not seriously affected 
by the woolly elm bark aphis but the knotting and gnarling of 
twigs and trunks (fig. 62) of young elm trees disfigure them. The 
white elm appears to 
be its favorite host 
tree; 
How recognized. — 
When this insect is 
present and at work 
the -trunkr amd 
branches show rough- 
ened knots with 
clusters of a white, 
woolly substance and 
licelike insects dur- 
ing the spring and 
Frc. 62.—Work of woolly elm bark aphis on large elms at summer. 
Albuquerque, N. Mex. (Photograph by Whitesides, G 
Dec. 13, 1919.) Habits and rem- 
edies.— This insect 
spends its entire life on the elm bark so that treatment on this tree 
will effectively check its injurious activity. There should be no 
difficulty in controlling it with 40 per cent nicotine sulphate (p. 13), 
kerosene emulsion (p. 12-13), or a 5 to 7 per cent solution of a 
standard miscible oil (p. 12) applied to the bark, the latter in winter. 
GALL-MAKING INSECTS AND MITES. 
GENERAL. 
Leaves and branches of many kinds of trees, particularly oak, 
maple, hickory, and hackberry, are subject to a great variety of 
peculiar growths called galls, most of which are made by insects or 
mites and which may become so numerous at times as to appear 
alarming. They vary much in shape, size, color, and structure, each 
being so characteristic of the kind of insect that makes and inhabits 
it as to afford a reliable guide to the specific identity of the architect 
in very many cases. 
% Briosoma rileyi Thos. 
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