10 



CIRCULAE 3 7 3, U. S. DEPARTMENT OF AGRICULTURE 



TEMPERATURE, EXPOSURE, AND DOSAGE IN ETHYLENE OXIDE 



FUMIGATION 



It was found that when adult Japanese beetles were exposed for 2 

 hours to the vapor of 1 pound of ethylene oxide to 1,000 cubic feet 

 of space, 90 percent of them were killed at a temperature of 65° F., 

 96 percent at 70°, and 100 percent at 75°. One pound for 1 hour 

 killed 54 percent at 75° and 93 percent at 80°. When ethylene oxide 

 was used at the rate of 2 pounds per 1,000 cubic feet, 96 percent of 

 the beetles were destroyed at the end of 1 hour at a temperature of 

 75° and all of the beetles were destroyed when the temperature was 

 80° or the period of exposure was 2 hours. 



100 



90- 



£ 80- 



fe 70 



5 60 

 o 



2 



65 



70 



TEMPERATURE (°F.) 

 75 80 



85 



90 



BEETLES EXPOSED DIRECTLY TO VAPOR 1 



BEETLES IN CRATES OF FRUIT DURING EXPOSURE—-! 



2 12122 12 1 12 

 DOSAGES OF ETHYLENE OXIDE (POUNDS^ 

 2 | I ■ | 2 | I | 2 



TIME OF EXPOSURE (HOURS) 



i I 



Figure 7. — Results of fumigation of adult Japanese beetles with ethylene oxide for dif- 

 ferent periods, at different temperatures, and with different dosages per 1,000 cubic 

 feet. 



Experiments in which beetles were fumigated in boxes of fresh 

 fruit showed that it was necessary to use 2 pounds of ethylene oxide 

 per 1,000 cubic feet of space for a period of 2 hours at 75° F., to 

 obtain a 100-percent mortality. 



A summary of the various tests is presented in figure 7. 



EFFECT OF ETHYLENE OXIDE ON CERTAIN SMALL FRUITS 



In the summer of 1930, raspberries, blackberries, and blueberries 

 were fumigated with ethylene oxide at the rate of 2 pounds to 

 1,000 cubic feet of space for 2 hours at temperatures of 75° and 80° 



