Insects and Inss^cticidks 
39 
Remedies. —Spraying is ineffective. Destroy all badly infested 
trees by burning. Many of the grubs can be killed and the life of valu¬ 
able shade trees prolonged by squirting a small amount of carbon biv 
sulphide into the burrows and plugging them with mud. This will 
necessitate going over the trees several times during early summer. 
Fig. 33.—Cottonwood Boi'er, showing male and female moths. The female is larger. 
Cottonwood Borer. —A large reddish caterpillar, head shining 
black, body somewhat flattened, and when mature about three inches 
long, bores large holes or galleries in the trunks of the cottonwoods 
and poplars. It transforms to a large thick-bodied moth in June and 
July. See Figs. 32 and 33. 
Remedies. —This borer does not bring its borings out to the sur¬ 
face, SO it can be detected only by the discoloration of the bark, due 
to sap leakage. The borers sometimes can be dug out with a stiff 
wire, or the channels opened and carbon bisulphide injected. (See 
under I^DCUst Borer.) 
Boxelder Leaf-Roller. —This is very similar in appearance and 
habits to the Fruit Tree Leaf-Roller. It seems to attack boxelder ex- 
clusivel}^ in Colorado. 
Remedies. —See under Fruit Tree Leaf-Roller. 
Plant Lice on Ash, Elm, Willow, Boxelder, Locust, etc .—Most all 
of ou’* shade trees and shrubs are subject to the attacks of one or more 
