TREE INSECTS AND THEIR CONTROL 201 
ELM 
LEAF CHEWING INSECTS 
Elm-leaf Beetle 
Habits Attacks all Elms, especially 
and the English Elm. Causes 
Damage, leaves to fall; if not checked, it 
brings about complete loss of 
leaves and if repeated sufficiently often 
will cause the death of tree. 
The first sign of damage is the appear¬ 
ance of irregular holes in leaves in early 
spring. These come from attacks by the 
full-grown beetle, which has just come 
from its winter quarters in barns, sheds 
and similar shelter. At this time eggs are 
laid on the under side of the leaves. In 
June these eggs hatch into larvae or grubs 
which grow to be one-half inch in length; 
the larvae feed on the leaves, giving the 
leaves the appearance of skeletons or 
lacework. Within 15 to 20 days after 
hatching the larvae develop into pupae, 
or young beetles, which are to be found 
at the foot of the tree. Just before this 
change the larvae may be seen crawling 
down the trunk. In another week the 
young beetles become fully grown. 
The eggs are orange-yellow in color, 
and occur in clusters of from five to 
twenty, in irregular rows on the under 
side of the leaves. The larvae are yellow¬ 
ish black to blackish. The pupae are 
orange-colored. 
Remedy. The best control is by the use 
of arsenate of lead, by spray¬ 
ing, whenever and as often as there are 
signs of attack. This poison should be 
applied to the foliage in the early spring, 
just after the buds have burst, and again 
two weeks later. If rains fall after the 
spraying it may be necessary to apply the 
poison a third or even a fourth time. The 
poison must reach the under side of the 
leaves to be effective against the eggs and 
the larvae. The first spraying is intended 
to kill the adults and prevent the laying of 
eggs; the later sprayings are additional 
safeguards against possible survivors. 
To destroy the pupae at the base of the 
tree scalding water, thick soapsuds or a 
solution of kerosene should be poured 
over them in liberal quantities; this 
should be used promptly and repeated 
whenever and as often as may be neces¬ 
sary until all the insects are destroyed. 
The surface of the soil should be turned 
by digging, to expose any insects which 
may have buried themselves. In the case 
of a large tree it is sometimes necessary 
to climb to the forks of limbs and gather 
stragglers. 
Combined action on the part of the entire neighborhood is essential in undertaking 
the destruction of the Elm-leaf beetle. Unless all trees are treated, the results will 
be without value, as the beetles will travel from infested trees to those which may 
have been treated. Another factor in the importance of cooperative action is that 
expensive spraying apparatus is required for trees as large as Elms and this appar¬ 
atus should be owned by the town or city government or by a number of individual 
property owners. 
Brown-tail Moth 
Habits This leaf-eating insect causes 
and great damage in New Eng- 
Damage. land and a severe attack 
destroys leaves as fast as 
developed. The eggs hatch early in 
August, after having been laid in July in 
oblong clusters covered with brown hair 
on the underside of the leaves. The 
young caterpillars make tents for them- 
Remedies. Cutting off the winter 
tents and burning them is an 
effectual method of destroying this pest. 
This must be done before the caterpillars 
emerge in the spring. It is also useful to 
spray with arsenate of lead when the 
leaves are full grown and again when the 
caterpillars hatch. 
