20 



BULLETIN 1313, U. S. DEPARTMENT OF AGRICULTURE 



Table 3. — Toxicity offumigants to Sitophilus oryza {arranged in order of decreasing 



effect) — Continued 



Fumigant 



Methyl formate 



Isoamyl acetate 



Diethylamine 



m-Buty 1 mercaptan 



Bromoform 



o- and p-Dichlorobenzene 



Carbon disulphide 



s-Tetrachloroethane 



7i-Valeronitrile 



s-Dichloromethyl ether. .. 



w-Propyl alcohol 



m-Butyl alcohol 



Ethyl methylketone 



Eluorobenzene 



Chlorobenzene 



Chloromethyl ether 



■71-Propyl acetate 



-»i-Butyl bromide 



Tetrachloroethylene 



Ethyl sulphide 



Ethyl bromide 



Nitromethane 



Benzene 



Allyl"bromide 



^-Propyl bromide 



Acetal 



M ethylene chloride 



Thionyl chloride 



Acetonitrile 



-n-Butyraldehy de 



Ethylene chloride 



Carbon tetrachloride 



Chloroform 



Acetone 



Acetylene dichloride 



Trichloroethylene 



Ethylidene chloride 



Methyl sulphide 



Cyclohexane 



Methyl alcohol 



Ethyl mercaptan 



Amylene -- 



Carbon dioxide 



Minimum 

 concentra- 

 tion caus- 

 ing 100 per 

 cent mor- 

 tality in 24 

 hours 



Per cent 



3.90 



.90 



.90 



.90 



a .94 



1.00 



1.00 



1.10 



1.10 



1.13 



1.70 



3 1.70 



3 1.80 



3 1.90 



2.00 



3 2.20 



2.50 



2.60 



2.60 



2.90 



2.90 



3.60 



3.80 



3 3.90 



4.10 



4.30 



4.40 



3 4.50 



5.00 



5.50 



6.00 



6.90 



7.00 



8.20 



9.00 



10.00 



10.20 



10.40 



3 13. 00 



16.00 



3 19. 00 



40.30 



50.00 



Boiling 

 point 



'C. 

 32.3 

 139.0 

 55.0 

 97.0 

 150.5 

 175.0 

 46.0 

 147.0 

 141.0 

 105.0 

 97.4 

 117.0 

 79.6 

 84.9 

 132.0 

 59.5 

 101.6 

 101.0 

 121.0 

 92.0 

 38.4 

 101.0 

 80.2 

 70.0 

 70.8 

 102.2 

 47.6 

 78.0 

 81.6 

 77.0 

 83.5 

 76.7 

 61.2 

 56.5 

 55.0 

 88.0 

 59.2 

 38.0 

 80.8 

 64.7 

 37.0 

 22-37 

 -78.5 



Minimum 

 quantity 



causing 100 

 per cent 



mortality 



in 24 hours 



Lbs. per 



1,000 cu. ft. 



1.51 



'3.26 



1.83 



2.26 



6.62 



4.10 



2.12 



5.15 



2.55 



3.62 



2.85 



3.51 



3.62 



5.09 



6.27 



4.94 



7.11 



9.93 



12.02 



7.29 



8.81 



6.12 



8.27 



13.15 



14.05 



14.15 



10.42 



14.92 



5.71 



11.05 



16.55 



29.58 



23.29 



13.27 



24.31 



36.62 



28.13 



18.00 



30.48 



14.28 



32.89 



78.76 



61.32 



Cost per 

 pound 



Dollars 



1.59 



.91 



16.33 



36.29 



2.04 



.15 



.06 



1.13 



27.22 



27.22 



1.36 



.76 



.30 



.09 



13.61 



2.27 



4.54 



1.13 



2.27 



.40 



9.07 



4.04 



15.88 



13.61 



18.14 



6.80 



9.07 



18.14 



13.61 



.68 



.082 



.32 



.20 



.36 



22.68 

 45.36 

 22.68 

 6.15 

 9.07 

 9.07 

 .07 



Cost per 

 1,000 cubic 



Dollars'. 



2.4J0 



2.9J 



29.88 



82.02 



13.50 



.615 



.127 



5. 82-. 



69.41 



98.54 



3.88 



2.67 



1.09 



67.23 



16.14 



45.08 



13.58 



16.54 



3.52 



55.51 



.33 



208.82 



191.22 



256. 68 



70.86 



135. 32 



103.58 



150. 39 



11.25 



2.44 



7.45 



2.65 



13.18 

 637.99 

 816. 48 

 691.29 



2.14 

 298.31 

 714. 35 



4.29 



3 Minimum concentrations tested. 



4 Chemically pure, in drums, sold for 30 cents a gallon. 

 ' Purified, in drums, sold for $1 a gallon. 



While the volatility of organic compounds at ordinary temperatures 

 is not proportional to their boiling points, very few data on the vapor 

 pressure of these compounds at ordinary temperatures are available. 

 For that reason the boiling points were used in this investigation. 

 The compounds are arranged in the order of decreasing toxicity. 



Moore (15) states: 



In general, the toxicity of a volatile organic compound is correlated closely with 

 its volatility. A decreasing volatility is accompanied by an increased toxicity. 

 The boiling point of the chemical is a general index of its volatility. Compounds 

 with boiling points of 225° to 250° C. are usually so slightly volatile that they 

 do not produce death except after very long exposures. 



If this theory is true, the boiling points of the compounds should 

 show a decrease, indicating increasing volatility, but no well-defined 

 relation between the toxicity and the boiling point is shown in Table 3. 

 This is not in agreement with Moore's theory. 



