102 U . S . BUREAU OF CHEMISTRY NOTES. [J. I". I.

FUMIGATION OF STORED-PRODUCT INSECTS WITH CERTAIN ALKYL AND ALKYLENE FORMATES. 3

By R. T. Cotton and R. C. Roark.

[ABSTRACT.]

THE vapors of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, isoamyl, and allyl formates were tested against rice weevils, clothes moths, carpet beetles, and furni- ture beetles. All were toxic to these insects. None of the formates tested had an adverse effect upon the germination of wheat. All these formates, except the methyl and ethyl formates, can be made free from fire hazard by the addition of carbon tetrachloride to the extent of from 6o to 75 per cent. by volume of the mixture.

FUMIGATION TESTS WITH CERTAIN ALIPHATIC CHLORIDES. 4

By R. C. Roark.

[ABSTRACT.']

TWENTY-ONE aliphatic chlorides were tested against rice weevils in flasks half filled with wheat, and against larvae of the clothes moth, black carpet beetle, and furniture beetle in a 5oo-cubic foot fumigating vault. I t was found tha t several of the chlorides possess toxicity to stored product insects. From the s tandpoint of availability, cost, effectiveness and freedom from fire hazard ethylene dichloride in a mixture of 3 volumes of ethylene dichloride to I of carbon tetrachloride appears to be the most promising as a general fumingant. Although more toxic than ethylene dichloride, tert-butyl chloride requires a larger proportion of carbon tetrachloride to render it free from fire hazard and cannot be used in metal- lined vaults owing to its tendency to break down and at tack the metal. Trichloroethylene is non-inflammable and shows considerable toxicity in vaul t fumigation at temperatures of 80 ° F. or over. None of the materials injured the germination of wheat.

3 Published in Ind. and Eng. Chem., 2o: 38o-382, April, I928. Published in d. of Economic Entomology, 2i : i35-I42 , Feb. I928.