13 
and lower branches of the trees can be reached. In eastern Xew 
England the poplars and willows are usually attacked by borers, 
so that many of the large limbs are in a weakened condition, and 
as the wood is naturally very brittle it is usually inadvisable to climb 
the trees in order to apply treatment. 
If the infestation is extremely heavy or the larvae swarm on 
buildings or enter houses, they can be swept to the ground and killed 
by crushing. Cases are on record where the larvae were washed from 
buildings by using water pressure, and afterwards were crushed 
on the ground. 
Experience has shown that the most effective treatment for the 
satin moth is to spray the trees infested by it with arsenate of lead 
(fig. 4) during the period when the caterpillars are feeding. 
Fig. 4. — Carolina poplars. The foliage on the trees in the rear was sprayed with 
arsenate of lead. The trees in the foreground were not sprayed, and were 
heavily fed upon by larvae of the satin moth. 
As the eggs are deposited anywhere on the trees, the feeding by 
the young larvae is well distributed on the foliage. It is not neces- 
sary to spray in August unless the infestation is very heavy. Should 
this be the case, an even distribution of the poison will give excellent 
results. If the spray is applied as soon as the larvae begin to feed 
it will be most effective. Both sides of the foliage should be sprayed. 
Summer spra}'ing will not as a rule be necessary. In the spring, 
as soon as the trees are in full leaf, treatment should be applied. A 
high-pressure sprayer is required in order to treat the tops of the 
trees. A machine of this type, using a solid-stream spray, has given 
excellent results in Massachusetts, when arsenate of lead was applied 
at the rate of 6 pounds of powder to 100 gallons of water. 
Because of the smooth surface of the foliage of poplar and willow 
trees, the poison does not adhere to it as well as to other types 
of foliage. Kecent experiments at the Gipsy Moth Laboratory indi- 
cate that excellent adhesion can be obtained by adding 3 quarts of 
