TWELVE] OUR RIVALS—THE INSECTS 
into California, where it wrought astonishing 
havoc. The young crawl for a while, and then 
settle down in vast numbers, sucking the life out of 
a tree. An orchard will be destroyed in a single 
season, and the most beautiful neighborhood will 
in a short time become a desert. It breeds on such 
trees as walnuts and willows, and on your berry 
plants, your lilacs, and most other shrubs, as well 
as on all fruit trees. All scales poison the wood, 
as well as suck the sap, which to some degree is 
true also of aphides. Besides the remedies named, 
we must bear in mind that a healthy tree is very 
much less likely to be assailed than a sickly tree, 
therefore keep up steady growth. 
Besides these almost domesticated enemies of 
our peace, each year is pretty sure to develop some 
special insect or worm, like the pear psylla, which 
gave us so much trouble in 1903. Forest worms 
are found to come in periods of about thirty years. 
Different sorts of borers move across the country, 
sometimes westward and sometimes eastward. 
The remedies which I have named are, as a rule, 
what we need for these special visitors, only attack 
them promptly before they get good lodgment. 
Prof. Roberts, of Cornell University, says the worm 
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