SODIUM CYANID FOK FUMIGATION PURPOSES. 89 
cyanid. This revision is accomplished by using a high-grade sodium 
cyanid with dosages one-fourth less than the amounts scheduled 
for the potassium salt. Thus if a dosage recommended should read 
that it requires 12 ounces of potassium cyanid to secure certain 
results against a particular insect the same results could be accom- 
plished with 9 ounces of a high-grade sodium product. In general 
fumigation against the purple scale {Lepidosaphes beckii Newm.), 
the writer has recommended a full schedule No. 1 of potassium 
cyanid. 1 Should one desire to produce the same results against this 
insect with sodium cyanid, he would use a schedule one-fourth less, or 
dosage equal to three-fourths of the dosage amounts given in schedule 
No. 1 of potassium. Such a three-fourths schedule with high-grade 
sodium cyanid will produce practically the same amount of gas as the 
full schedule No. 1 of potassium. 
Plate IX gives such a schedule, which is called schedule A for 
sodium cyanid. 1 By using this schedule with a 124 to 130 per cent 
cyanid of sodium practically the same results will be secured as with 
full schedule No. 1, as given in Part I of this bulletin, with potassium 
cyanid. 
These dosages are in ounces and are based on a knowledge of two 
measurements of the tree — the distance around the bottom and the 
longest distance over the top. Having secured these two distances 
for any tree, the dosage for that tree may be found in that part of the 
table where the lines for these measurements intersect. 
DOSAGES RECOMMENDED FOR SCALE PESTS. 
Purple scale. — In general fumigation for the purple scale (Lepido- 
saphes beckii Newm.) use full schedule A of sodium cyanid (Plate IX). 
With its use all insects and more than 99 per cent of the eggs are 
destroyed on the leaves and branches. Exposure should last 1 hour- 
Red scale. — For the red scale (CTirysomphalus aurantii Mask.) 
use a three-fourths schedule (three-fourths of schedule A of sodium 
cyanid [Plate X]), An exposure of 45 minutes is sufficient. 
Yellow scale. — For general work against the yellow scale (Chry- 
somphalus citrinus Coq.) three-fourths of schedule A of sodium 
cyanid (Plate X) will prove satisfactory. The section in which the 
yellow scale is most serious is about Redlands, San Bernardino County, 
where a great acreage is planted on terraced land. Owing to the 
irregular topography of terraced orchards the tents seldom lie as 
closely to the ground as on level land, and as a consequence there 
usually is a greater amount of leakage. For terrace fumigation 
full schedule A (Plate IX) should be used. Exposure should be 45 
minutes. 
1 For detailed use of such schedule, as well as methods of measuring trees, see pp. 34-37, Part I, of this 
Bulletin. 
