60 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
CaHAs0 4 . Commercial samples in this test did not compare so 
favorably. There would appear to be a considerable dilution of the 
arsenates here. It is believed that this dilution of the commercial 
samples was in an endeavor to reduce the burn and not an attempt to 
adulterate the spray material. F. E. DeSellem (5) of North Yakima, 
Washington, reports in 1916 very favorable results against codling 
moth with a commercial calcium arsenate. At a dilution of half pound 
to 50 gallons he obtained a total of 99.5 per cent clean fruit. 
Field Tests 
Field spraying experiments have been undertaken by several in¬ 
vestigators with varying degrees of success. A fairly elaborate series 
of tests were outlined at the Oregon Station, but due in part to un¬ 
favorable weather conditions and in part to war emergency entomologi¬ 
cal activities, the experiment finally resolved itself into a rather pre¬ 
liminary test of pure and commercial calcium arsenates alone and in 
combination. 
The following materials and combinations were used: 
Neutral-calcium arsenate Ca 3 (As0 4 ) 2 
Acid calcium arsenate CaHAs0 4 
Calcium ammonium arsenate CaNH 4 As0 4 
Latimers calcium arsenate Commercial 
Riches Piver calcium arsenate Commercial 
These materials were used alone and in combination with an excess 
of CaO and of lime-sulphur at strengths of 2-50, 1-100, and 1-400. 
For example, neutral calcium arsenate was used as follows: 
1 . 
2 . 
3. 
4. 
5. 
6. 
7. 
8 . 
9. 
Ca 3 (As0 4 ) 2 
u 
li 
a 
(i 
a 
n 
a 
a 
2-50 = (at the rate of 2 pounds to 50 gallons) 
2-50 plus lime 1-50 
2-50 plus L.S. 1-40 
1-100 
1-100 plus lime 
1-100 L.S. 
1-400 
1-400 plus lime 
1-400 plus L.S. 
The trees were six-year-old apple and all materials were applied in 
duplicate—the date of application was June 15. Observations on 
burn were made, June 19, June 22, June 27, July 2, and July 18. 
A mass of notes were compiled from these field tests but are not 
deemed sufficiently conclusive from this preliminary experiment to 
warrant taking time for more than a brief summary: 
1. The commercial materials showed decidedly better adhesive 
properties than did the pure materials. 
2. The check trees, those without the addition of either lime or of 
lime-sulphur, gave a decided burn, accumulative in action. 
