FUMIGATION OF CITRUS PLANTS. 25 
EXPERIMENT 26. 
Condition during fumigation, shade, 86°-91° F. 
Dosage, !3 ounces KCN. 
Date, March 18, 1915, 2.05-3.05 p. m. 
Plants in each test, 2; total, 20. 
Remarks: Temperature of fumigatorium was raised from about 75° to 91° F. im- 
mediately betore fumigation and maintained at temperature of 86°-91° F. through- 
out the treatment. 
Results. 
Condition after fumigation. 
Condition before = 
fumigation. Dark, 63° | Shade, 65° | Dark, 91° | Shade, 95°} Sun, 74° 
Re F. F. | 18, F. 
fy Dank, 63°C Rol 414 Boe Bard ee lyre A 4 
Sinn al eae 4 4 4 5 
} 
EXPERIMENT 27. 
Condition during fumigation, shade, 61°-70° F. 
Condition before fumigation, shade, 54° F. 
Dosage, 14+ ounces KCN. 
Date, March 30, 1916, 7.12-8.02 a. m. 
Plants in each test, 6; total, 12. 
Remarks: Temperature of fumigatorium was raised from 54° to 70° F. during appli- 
cation of gas and was held ata fluctuating temperature of 61°—70° F. during treatment. 
Rise in temperature was accomplished in 2 to 4 minutes. 
Results. 
Condition after fumigation. 
Shade, 57° F. | Sur, 61° F. 
RESULTS. 
The experimental evidence presented in this paper indicates that 
for citrus trees the safest temperatures surrounding fumigation fall 
below 80° F. Yet in experiment 27, in which the temperature at no 
time departed from this optimum, the plants were almost defoliated. 
Experiments 3 and 8 were conducted with equally tender piants, 
with the same dosage, with the same exposure in one case though a 
little less in the other, and at comparable prefumigation and post- 
fumigation temperatures, yet the plants in these two experiments had 
merely the tender growth burned. A detailed comparison of experi- 
ments 3 and 27, however, shows a difference in temperature fluctua- 
tions during the exposure to gas, it appearing that experiment 3 was 
performed at a constant temperature of 57° to 58° F., whereas in 
