203 
April, ’20] PETERSON: PEACH-TREE BORER 
Table II. The Effect of Sodium Cyanide on Peach-Tree Borers (per Tree) Present in Nine- 
Year-Old Trees in May, 1919, at Clementon, N. J. 
Series 
Treatment 
Larvae per tree (alive) 
Reduction (percentage) 
A 
1 oz. to 1 gal. 
1.6 
68% 
B 
oz. to 1 gal. 
0.6 
88% 
C 
1 oz. dry 
1.0 
80% 
D 
1| oz. dry 
0.0 
100% 
E 
Check 
5.0 
Series A-E in gravel loam soil. 
centage of kill is based on a comparison of the number of living larvae 
removed from the treated and check trees. Heavily infested trees 
were chosen for these experiments. 
Table III. The effect of sodium cyanide on the total number of larvae found 
in the three zones of trees (8 years old). Oct. 1. 1919, Middletown, N. J. Sandy 
loam soil. Ten trees in each plot. 
Table III shows the results obtained October 1, 1919, at Middle- 
town, N. J. Twenty heavily infested trees were selected and treated 
in this severely infested orchard, ten trees with one ounce of sodium 
cyanide dissolved in one gallon of water for each tree and ten trees with 
one ounce of dry sodium cyanide sprinkled in a shallow trench about 
each tree. When the larvae were removed, their condition, size and loca¬ 
tion in the tree was noted. The diagram shows the tree divided into 
three zones, the top or above ground zone extending from one inch 
above the soil level upwards and the bottom or below ground zone 
extending from one inch below ground downwards to and including 
the base of the large roots. The intermediate zone, where the greatest 
concentration of larvae was found, may be called the soil level zone. 
