FUMIGATION AGAINST GRAIN WEEVILS 



35 



"old process" and "new process" grades of ethyl acetate completely 

 volatilized from the gram, so that no odor was noticeable in the 

 process of milling, and the loaf, hot or cold, had only the natural 

 odor and flavor (samples 11024 and 11025 in Tables 10 and 11). 



The suitability of a sample of ethyl acetate for fumigating grain 

 should be determined by the following test: Wet a sheet of filter 

 paper (11-centimeter diameter is a convenient size) with the ethyl 

 acetate, and allow it to evaporate, noting the odor from time to 

 time. No foreign odor should be present, and the liquid should 

 volatilize completely without leaving any odor. The carbon tetra- 

 chloride to be mixed with the ethyl acetate should be similarly 

 tested, and should likewise be free from odoriferous constituents of 

 low volatility. The presence of sulphur compounds in carbon tetra- 

 chloride is particularly objectionable because they give a garlicky 

 odor to the fumigated grain. Ethyl acetate and carbon tetrachloride 

 of a grade which satisfies this test are now commercially available 

 in large quantities at a price but slightly higher than that asked for 

 the commercial grades. 



ADDITIONAL FUMIGATION TESTS WITH ETHYL ACETATE AND 

 CARBON TETRACHLORIDE 



In August and September, 1924, car fumigation tests were made 

 with a mixture of ethyl acetate and carbon tetrachloride combined 

 in a ratio that would make a noninflammable product at ordinary 

 temperatures. The results are shown in Table 14. 



Table 14. — Results of fumigation tests on weevils in wheat in box cars, using a 

 mixture of 40 volumes of ethyl acetate with 60 volumes of carbon tetrachloride 













Insects killed at different levels after exposure for 









Rela- 







24 hours 







Mean 

 tem- 



tive- 

 humid- 



Con- 

 cen- 



Aver- 

 age 





Insects 



Date 





















o 



in 





pera- 

 ture 



ity 

 (noon) 



tration 



mor- 

 tality i 



> 



IN 

 > 



CO 



> 



> 



ID 



> 



to 



> 



ID 

 > 



00 



s 



> 



OS 



ID 

 > 



CD 



grain 3 













CD 



01 



CD 



a 



ID 



CD 



CD 



ID 



CD 



CD 















lA 



-J 



Hi 



J 



>J 



>A 



J 



(-} 



J 











Lbs. per 

































1,000 





Per 



Per 



Per 



Per 



Per 



Per 



Per 



Per 



Per 



Per 





1924 



"F. 



Per cent 



cu.ft. 



Per cent 



cent 



cent 



cent 



cent 



cent 



cent 



cent 



cent 



cent 



cent 



Per cent 



Aug. 26 



78 



68 



30 



80 



100 



100 



50 



50 



50 



100 



50 



100 



100 



100 



100 



26 



78 



68 



40 



96 



100 



100 



100 



100 



100 



80 



80 



100 



100 



100 



( 3 ) 



27 



78 



41 



40 



99 



100 



100 



100 



100 



100 



100 



90 



100 



100 



100 



100 



27 



78 



41 



40 



99 



100 



100 



100 



100 



100 



90 



100 



100 



100 



100 



100 



27 



78 



41 



40 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



99 



28 



80 



61 



50 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



Sept. 3 



66 



63 



40 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



3 



66 



53 



40 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



100 



4 



66 



45 



40 



4 86 



100 



100 



100 



100 



100 



80 



90 



90 



80 



20 



100 



6 



60 



41 



40 



98 



100 



100 



100 



100 



100 



100 



100 



80 



100 



100 



( 6 ) 



6 



60 



41 



40 



97 



90 



100 



90 



100 



100 



100 



100 



100 



100 



90 



(') 



2 



78 



51 



40 





No weevils; sampled for milling and baking tests. 





2 



78 



51 



40 





Do. 





2 



78 



51 



40 





Do. 





2 



78 



51 



40 





Do. 





1 For insects exposed in pill boxes. 



1 The grain in all but six of the cars fumigated was moderately infested with weevils. The percent- 

 ages given in this column represent the kill of this infestation. 



* A few alive in ends of car. 



4 Fumigation interrupted when halfway through for 10 or 15 minutes, during which time the car door 

 remained open. 



'- No weevils. 



