Some Insects Attacking the Peach. 7 
The eggs are pearly white, changing to a deep yellow before 
hatching. They are quite conspicuous, being about ^ of a milli¬ 
meter (1/60 of an inch) in length by mm. (1/120 inch) in 
breadth. 
These observations of the egg and egg-laying habits of the in¬ 
sect, made in California by Mr. Clarke, are very interesting, as they 
are the first recorded from studies made under the natural condi¬ 
tions of the orchard. 
Experiments for Control of the Twig-borer .—The experiments 
testing different insecticides for the control of this pest, were all con¬ 
ducted in the spring of 1910, and were combined with the green- 
peach aphis experiments recorded in this bulletin, with the discus¬ 
sion of the latter pest. 
The comparative scarcity of twig-borer the past season made it 
difficult to secure much reliable data from the experiments. Table 
I was compiled from data gathered in the W. C. Strain orchard at 
Clifton, and Table III gives general results of all the experiments 
in both the Strain and Paxson orchards. 
TabeE 1. 
Results attained with different insecticides in controlling the peach 
twig-borer, in the W. C. Strian orchard at Clifton, Colo. 
Insecticide Used 
Strength 
Used 
Date 
Sprayed 
Dale 
Examined 
Wilted 
Tips 
Trees 
Examined 
Black Leaf-, 
1-30 
March 7 
April 26 
5 
3 
Black Leaf . - - - 
1-40 
U 
U 
6 
3 
Black Leaf 
1-50 
U 
u 
3 
3 
Black Leaf - - - 
1-70 
a 
u 
0 
1 
Black Leaf “40”-- -- 
1-600 
tt 
• 0 
2 
Black Leaf “40” _ 
1 800 
u 
t t 
7 
4 
Black Leaf “40”_ 
1-1000 
u 
u 
6 
4 
Lime and Sulfur.- - . 
1-10 
u 
°i 
12 
Lime and Sulfur. - - - 
1-11 
u 
o S 
Soluble Oil- - — - 
1-20 
u 
4 
2 
Unsprayed- — 
16 
4 
While it is not thought that this year’s experimental work with 
twig-borer, would justify the drawing of many conclusions, there 
were at least some helpful hints gathered in regard to its control. It 
may be seen from Table I that “Rex” Lime and Sulfur gave perfect 
results. More trees were sprayed with the “Rex” mixture 1-10 and 
1-11, than with any other insecticide, yet in a very careful examina¬ 
tion of 12 trees by Mr. Strain and myself, we failed to detect the 
presence of a single wilted twig because of the work of the borer. 
On 4 check trees in the same block 16 wilted tips were counted, and 
on 22 trees sprayed with tobacco preparations and soluble oil, 3 \ 
wilted tips in all were counted. One tree sprayed with Black Leaf 
