54 MISSOURI BOTANICAL GARDEN BULLETIN : 
bating this insect is to find and “dig him out”; the “dig- 
ging out” will rarely do more injury than the borer would 
otherwise cause. 
A precautionary measure, which frequently does con- 
siderable good, is to spray the trunk and larger branches in 
the spring and again during June and July with a wash 
made as follows: Thin one gallon of soft soap with an equal — 
amount of hot water and stir in one pint of crude carbolic 
acid (one-half pint refined carbolic acid) ; let it stand over 
night and then add eight gallons of soft water. Only the 
most vigorous care and attention, particularly during the 
months from April to September, will save trees from the 
disfigurement and eventual destruction by this dangerous 
insect. 
Aside from the borers there are numerous leaf-eating in- 
sects which do considerable damage to trees. Chief among 
these are the bagworms. During the fall and winter the 
small bags hanging in thousands from the trees in the city 
are objects readily visible to anyone. Many of these bags 
contain eggs which hatch out about the time the first leaves 
begin to form on the trees. The young caterpillars quickly 
attack the leaves, and before the tree is fully leaved may, in 
some seasons, entirely defoliate it. 
The most effective method of guarding against these in- 
sects is to collect the bags in the winter time and burn them. 
In the spring, after the larvae have appeared, they may be 
controlled by spraying the trees with a solution of arsenate 
of lead. This solution may be prepared as follows: Acetate 
of lead, 12 ounces; arsenate of soda, 4 ounces; water, 15 
to 20 gallons. Dissolve the two salts in separate vessels, 
using small quantities of water, and pour the two solutions 
etuliensonaly into the tank containing the 15 to 20 gallons 
of water. 
f Various forms of web worms destroy. the leaves of shade 
{ trees during the latter part of the summer. These insects 
i 
f 
\ 
can be destroyed by cutting out the twigs in which the nests 
| of the caterpillars are located and burning them. It is al- 
ways better to cut out the twigs than to burn them while 
on the tree. 
During the last few years the soft maple trees in St. Louis 
have been very frequently attacked by the cottony maple 
scale. This insect attacks the soft maple in particular. 
During the winter the females are oval, brown, disk-like 
