FUMIGATION OF FRUIT TO DESTROY JAPANESE BEETLE 



90°, and 100 percent at 95°. A concentration of 2y 2 pounds of the 

 compound to 1,000 cubic feet for 2 hours Avas required to destroy 

 all the beetles at 95°, 7% pounds for 2 hours at 90°, and 10 pounds 

 for 2 hours at 85° and 80°. Ten pounds for 2 hours at 75° killed 

 only 96 percent. 



No experiments were performed at temperatures of less than 75° 

 F. because the fumigation house was not equipped for lowering the 

 temperature and the work was done during the summer months when 

 adult Japanese beetles were available. 



It is apparent that for practical work it is not advisable to try 

 fumigation with carbon disulphide when the temperature is below 

 80° F. and that the most effective and economical work can be done 

 at higher temperatures. 



ioo 



£90 



80 



70 



o 60 



50 



95 



TEMPERATURE (°F.) 

 90 85 



10 7.5 5 2.5 10 7.5 5 2.5 10 7.5 5 2.5 10 7.5 5 

 DOSAGE OF CARBON DISULPHIDE (POUNDS) 



10 



Figure 3. — Results of fumigating Japanese beetles with carbon disulphide vapor for 

 hours, at different temperatures and with different dosages per 1,000 cubic feet. 



TIME OF EXPOSURE IN FUMIGATION WITH CARBON DISULPHIDE 



It was found, as shown in figure 4, that a dosage of 10 pounds of 

 carbon disulphide to 1,000 cubic feet was 100 percent effective when 

 the treatment was prolonged to 2 hours, but that this dosage was 

 only 99 percent effective with an exposure of 1 hour, unless the tem- 

 perature was as high as 95° F. Since 15 minutes normally is re- 

 quired to vaporize the carbon disulphide and to obtain the desired 

 concentration, the exposure should be not less than 2 hours, to assure 

 complete destruction of the beetles. 



PENETRATION OF CARBON DISULPHIDE INTO BASKETS OF FRUIT 



The nature of the material to be fumigated has a bearing on the 

 effectiveness of the treatment. Grain, flour, soil, or other compact 

 materials must be exposed to the gas for longer periods than more 

 porous or less compact materials. Fresh fruits, when packed for 



