6 BULLETIN 424, U. S. DEPARTMENT OF AGRICULTURE. 
Table I. — Record of damage by the cottonwood borer (Plectrodera scalatorj to 
10 trees at Garden City, Kans., 1913. 
Tree No.— 
Total. 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Egss 
2 
9 

2 

5 
1 
2 

4 
2 
1 

6 
1 
2 



14 

2 

8 

8 

6 

2 

9 

1 
2 
Small larvae 
10 
78 
Large larva; 
Tunnels 

o 


4 
20 
The total of the eggs and small larvae was 80. an average of 8 to a 
tree. Such a number of young larvae, nearly all of which were 
working in the bark, would seriously check the growth of the tree, 
as well as render the tree liable to damage by heavy winds. 
PREVENTIVE. 
Since the eggs are placed only on the trunks of the trees at 
the surface of the ground, infestation is easily prevented by a screen 
cone about a foot 
high, wrapped about 
the base of the 
tree and with its 
lower edge sunk in 
the ground. This 
cone should fit the 
tree trunk closely at 
its top to exclude the 
beetles and be set out 
at the base an inch 
or two to prevent the 
eggs from being de- 
posited through it. 
It can be made by 
cutting common win- 
dow screen, usually 
galvanized netting, 
one-fourth to one- 
half inch mesh, into 
strips about 1 foot 
wide and of the 
proper length. Each strip is then slit from a third to half way 
across from one edge at distances of from 3 to 4 inches, as shown 
in the diagram (fig. 3). The screen is then wrapped around the 
tree, the lap fastened at its lower end with a nail, pin fashion, and 
Fig. 3. — Diagram showing method of protecting trunk of 
cottonwood against attack by the cottonwood borer. At 
left, section of screen ; at right, cottonwood trunk show- 
ing screen in position. Reduced. (Original.) 
