HOW THE FOREST IS GUARDED 103 
Brought over from Europe for experiment purposes 
about forty years ago they escaped by accident and 
were not heard of for some time. When their activities 
near Boston were noticed an appropriation was made 
for a few years but against the recommendations of 
experts this appropriation was discontinued for about 
five years because they appeared to be extinct. In 
reality two or three years’ more work would have exter- 
minated them completely. With the cessation of pre- 
ventive measures the moths increased rapidly and as 
a consequence they spread from Massachusetts to prac- 
tically all of the New England States. In Massachusetts 
alone nearly $1,000,000 per year is spent by the State, 
Federal Government, and private individuals to con- 
trol these destructive insects. 
Leaf-eaters like the larve of the gypsy and brown- 
tail moths, the elm leaf beetle, etc., can be killed by 
poisoning their food. A solution of lead arsenate is 
sprayed upon the leaves and the caterpillars die by the 
thousand after eating the leaves. However, the difficulty 
and expense of spraying thousands of acres of wood- 
land is at once apparent and unless the natural enemies 
multiply and can take care of a large part of the 
annual crop of these pests, neighboring States must 
certainly be invaded by hungry armies of insects. By 
creosoting the egg masses, by removing trees to which 
they are especially partial and by breeding and 
liberating parasites it is hoped to keep them in check. 
Fungi.—The harmful effects of fungus disease are 
noticed both on living and dead timber. Those found on 
dead timber are called ‘‘saprophytes’’ and are not 
especially dangerous. Of the parasitic fungi—those 
that attack living trees—one of most impertance at 
present is the chestnut bark disease—Hndothea para- 
