April, ’24] 
SULLIVAN: CALCIUM CYANIDE FOR FLEAS 
235 
burning, otherwise the plants were not injured. It requires two treat¬ 
ments to thoroughly clean out an infestation of white fly. 
A greenhouse containing over fifty different kinds of plants was fumi¬ 
gated December 17, 1923 using one ounce calcium cyanide dust to 1,000 
cu. ft. A 95% killl of white fly was obtained and no plants were 
injured. A temperature of 60 F. was maintained and the house was 
allowed to fumigate from 7 P. M. to 7 A. M. Calcium cyanide dust- 
used at the rate of one ounce to 2,000 cu. ft., temperature 60° F., gave a 
25% kill. The ease and safety with which calcium cyanide can be used 
seems to indicate that it has possibilities of becoming the standard 
remedy for the control of white flies in greenhouses. Its effect upon 
other greenhouse pests has not as yet been studied. 
On November 13, 1923 a series of experiments were started to de¬ 
termine the value of calcium cyanide for fumigating nursery stock 
infested with San Jose Scale (Aspidiotus perniciosus Comst.), apple 
and peach trees were used. The apple trees had two seasons growth 
from graft, the peach trees were cut backs but with two seasons growth. 
They were grown in an experimental nursery and were badly infested 
with San Jose Scale. Many of the peach were almost encrusted. A 
tight fumigating box was used. Calcium cyanide dust was used at the 
rate of 1 oz. to 25 cu. ft.; 1 oz. to 50 cu. ft.; 1 oz. to 100 cu. ft.; 1 oz. 
to 200 cu. ft. and 1 oz. to 400 cu. ft. Five sets of trees were used for 
each strength. The first set was allowed to fumigate for 30 minutes; 
the second 45 minutes; the third 1 hour; the fourth 1% hours and the 
fifth 2 hours. The trees were dug and placed directly in the fumigating 
box. The desired quantity of calcium cyanide dust was then spread 
out on a dry board placed in the center of the box about half way 
between the bottom and top. After fumigating the trees were reset, 
and ten days later the first counts were made. With every test enough 
scales were counted to get a fairly accurate average of the percentage 
of scale killed. The first or the ten day count showed that none of the 
treatments resulted in a ’ 100% kill. In one case (1 oz. to 200 cu. ft. 
for 30 min.) only 70% of the scales were dead but in most cases the 
kill was better than 90%. About three weeks after fumigating counts 
were again made on the first three sets of trees. This time 100% 
of the scale were dead in eight out of fifteen cases. Then again about 
five weeks after fumigating the third counts were made on all of the 
twenty-five different tests.. Live scales were found only on nine. 
The following table shows a complete record of all counts made and the 
results obtained. 
