FUMIGATION OF FRUIT TO DESTROY JAPANESE BEETLE 9 



the furniture carpet beetle, Anthrenus vorax Csy. ; the rice weevil, 

 Sitophilus oryzae L. ; the Indian-meal moth, Plodia interpwnctella 

 Hbn. ; the saw-toothed grain beetle, Oryzaephilus surinamensbs L. ; 

 the red-legged ham beetle, Neorobia ?*wfipes DeG. ; and the confused 

 flour beetle, Tribolium confusum Duv. 



Ethylene oxide, according to Back, Cotton, and Ellington (i), 

 has been used as a fumigant with success in destroying infestations 

 of the webbing clothes moth, the furniture carpet beetle, the confused 

 flour beetle, the rice weevil, and the saw-toothed grain beetle. 



PROPERTIES OF ETHYLENE OXIDE 



The physical properties of ethylene oxide have been described 

 recently by Back, Cotton, and Ellington (i), and by Eoark and 

 Nelson (7). 



At ordinary temperatures it is a colorless gas ; at low temperatures 

 it is a mobile colorless liquid that boils at 10.5° C. (50.9° F.). The 

 specific gravity of liquid ethylene oxide is 0.887 at 7°/4° C. (44.6°/ 

 39.2° F.). The empirical formula is C 2 H 4 0. The molecular weight 

 is 44.031. The concentrations up to 3% pounds per 1,000 cubic 

 feet of space are nonexplosive and noninnammable. The ignition 

 point is 434° C. (813.2° F.). Ethylene oxide has a faint but distinct 

 etherlike odor, and the vapor is approximately 1.7 times as heavy as 

 air. The vapor exhibits remarkable penetration into such compact 

 materials as soil. The vapor of ethylene oxide, while not highly 

 toxic to man, should not be inhaled extensively. 



EFFECTIVENESS OF ETHYLENE OXIDE AS A FUMIGANT 



The effect of ethylene oxide as a fumigant for fresh fruit was 

 determined in the experimental fumigation house described in a 

 previous section of this circular. 



In the summer of 1930 some 16,000 adult Japanese beetles were 

 fumigated, under various conditions, with ethylene oxide to deter- 

 mine the best conditions for killing 100 percent of them. In one 

 series of tests the beetles were exposed directly to the vapor in 

 rectangular cages 24 inches long, 11 inches wide, and 14 inches high. 

 The sides and tops of these cages were covered with wire screen and 

 each was provided with a door. In another series of tests the beetles 

 were treated while contained in baskets of fruit. Immediately be- 

 fore treatment, several boxes placed in various parts of each layer 

 of a crate of fruit were artificially infested with beetles. 



In the various experiments the insects were placed in the fumiga- 

 tion house as soon as the desired temperature was reached. In each 

 experiment the proper dosage of ethylene oxide was measured as a 

 liquid and poured into shallow pans that rested on a table. The 

 window and door of the house were closed and made tight. The 

 fan was started to circulate the ethylene oxide vapor, which evolves 

 rapidly at ordinary fumigation temperatures. After the desired 

 time had elapsed, the door and window were thrown open to venti- 

 late the room. The treated insects were taken to the insectary, where 

 they were examined, at the end of 24 and 48 hours, to determine the 

 number that were alive or dead. 



1539°— 35 2 



