34 
Orange, and some other counties in southern California are indicated 
in the subjoined table, published by the horticultural commissioners 
of Riverside County, Cal. 
TABLE 1.—Amounts of chemicals and water ordinarily used for trees of different 
sizes. 





Cyanide, | Sulphuric 
Height | Diameter P 
at dent otrirea Water. Cache Aaids by per 
Feet. Feet. Ounces. | Ounces. Ounces. 
4 2 1 1 
8 6 3 1k 
10 8 5 2 
12 14 11 5 
16 16 17 8 
20 16-20 22 10 
20-24 18-22 30 14 
24-30 20-28 34 16 
30-36 25-30 52 24 



The proportions here recommended are thoroughly effective for the 
black scale at the proper season, and measurably effective also for the 
California red scale and the purple scale. Where the treatment is 
designed to be one of extermination for these latter scale pests, 
from one-third to one-half more of cyanide and acid is employed, as 
indicated by the subjoined table, furnished by Mr. G. Havens, of 
Riverside. The amounts here recommended may be employed also 
for compact trees with dense foliage or in moist coast regions where 
stronger doses are needed. 
TABLE 2.—Hazcessive amounts of chemicals used for absolute extermination of 
scale insects.% 



¢ Diameter : Time to 
Peele through Water. Salppure Cyanide. | leave tent 
foliage. = on tree. 
Feet. Feet. Fluid ozs. | Fluid ozs.| Ounces. Minutes. 
6 — 4 3 1k 1 20 
8 5- 6 6 2% 2 30 
10 7-10 15 5- 6 4-5 35-40 
12 9-12 20- 30 7-9 53- 7% 40 
14 12-14 30+ 35 9-12 8 -10 40 
16 12-15 35- 40 12-14 10 -12 40 
18 14-16 45- 55 15-18 12 -15 40-50: 
20 16-18 60- 70 20-22 16 -20 45-50 
22 16-18 70- 75 22-25 20 50 
24 18-20 75- 80 25-30 22 -26 50 
7A 20-24 85-100 30-36 28 -32 60 
30 20-28 100-110 36-44 32 -38 60 

“A fumigation of the orangery of the Department, December 3, 1900, demonstrated that 
0.15 of a gram of cyanide to the cubic foot, or a little more than half an ounce to the 
hundred cubic feet, is completely exterminative of scale insects, effectually killing the 
eggs, even of the black, purple, and other scales. The strength mentioned is that 
ordinarily recommended for violet houses, and the results are scarcely comparable to 
the proportions recommended in Tables 1 and 2, for the reason that in these tables the 
amount of cyanide is greatly lessened with larger trees, and, furthermore, that the 
orangery probably retained the gas more effectually than would be the case with cloth 
tents. Nevertheless, it is interesting to know that a comparatively inconsiderable 
strength of cyanide, when applied under the best conditions, will prove thoroughly 
effective against the eggs as well as the insects in all stages. 
127 

