April, ’24] 
SASSCER & WEIGEL: GREENHOUSE FUMIGATION 
221 
Table II. Showing Control Obtained with Calcium Cyanide in Box 
Fumigation Experiments 
Dosage Condition after 
Exp. 
NaCN in 
Temperature 
: Humidity Interval 
fumigation 
Control 
No. 
Ounces 
°F 
% 
in days 
dead 
alive 
% 
I 
A 
71.6 
85 
1 
79 
94 
45.6 
2 
do 
69.2 
90 
l A 
370 
7 
98.1 
3 
69.4 
90 
1 
185 
2 
98.9 
4 
do 
71.6 
90 
1 
111 
50 
68.9 
5 
do 
72.5 
69 
1 
368 
15 
96. 
6 
1 
74.3 
67 
K 
280 
0 
100. 
7 
do 
68.9 
91 
l 
118 
15 
88.7 
8 
do 
80.6 
64 
l 
165 
2 
98.8 
9 
do 
82.4 
65 
1 
925 
30 
96.7 
10 
do 
80.6 
64 
l 
830 
0 
100. 
In the y 2 ounce equivalent dosage accurate records of mortality could 
not be made the same day because some individuals revived after being 
brought into fresh air. The aphids were only stupefied by fumigation at 
the y ounce rate when exposures lasted 15, 30, and 45 minutes respec¬ 
tively, and most of them soon recovered. 
After these tests were completed it was learned that spreading the 
dust directly on the moist newspapers caused complex reactions which 
may have reduced the amount of hydrooyanic-acid gas actually re¬ 
leased. 
♦ 
Plant tolerance tests of the dust were then made under greenhouse con¬ 
ditions. For this purpose 8 varieties of plants known to be very sensi¬ 
tive to hydrocyanic-acid gas were selected. Ten plants of each variety 
were fumigated at rates equivalent to Y, and 1 ounce of sodium 
cyanide per 1,000 cubic feet for one hour. The temperature and 
Table III. Showing Tolerance of Different Varieties of Plants when 
Fumigated under Greenhouse Conditions with Calcium Cyanide 
Degree of burning at dosages equivalent 
Host to sodium cyanide in ounces 
A 
24 
1 
Ageratum. 
. Slight 
None 
vSevere 
Coleus. 
. None 
None 
None 
Artemisia. 
None 
Slight 
Heliotrope. 
. Very slight 
Very slight 
vSevere 
Jasminum grandiflorum. 
. Tip very slight 
Tip slight 
Tip severe 
Lantana elegantissima. 
. None 
None 
None 
Ipomoea grandiflora /. 
. None 
None 
Slight 
Salvia. 
Slight 
Severe 
