TOXIC ACTION OF CERTAIN GASES. 11 
The results reported in Table 7 show that chloropicrin is more toxic 
than hydrocyanic acid to some insects, especially toward the stored- 
product insects. The mites, however, appear to be more resistant 
to chloropicrin than to hydrocyanic acid. __ 
To check the results obtained by Moore,! weevils, both flour and 
rice (Tribolium ferrugineum Fab., Calandra oryzae 1.) and Plodia 
interpunctella Hbn. larvee were fumigated with chloropicrin at the 
rate of 1 pound per 1,000 cubic feet. In the case of each insect, 50 
individuals were placed in glass cylinders, which were then covered at. 
both ends with gauze and put in the center of a 2-peck sack of oats 
where they were treated for 24 hours. On removal, all the insects 
were apparently dead, and none of them revived during a period of 
several days. 
Germination tests, made on a number of varieties of seeds which 
had been fumigated with saturated chloropicrin gas for various 
periods, gave the result shown in Table 8. 
TABLE 8.— Effect of chloropicrin on seea germination. 
Germination. 
1.75 per cent concentration 
‘ (temperature, 20° C.; rela- 
Kind of seed. tive humidity, 0). 
Check. 
30 60 120 
minutes. | minutes. | minutes. 
Per cent. | Per cent. | Per cent. | Per cent. 
Ailfaliag COmmMmONMe sesecceee ect aces eecasee. RES Seen s Sere iete isis leis 49.0 42.0 35. 0 41.0 
IBanleys; Morlanbaseowsssens coke ceiacic eae cine oe aie sees Seaton 100. 0 99.5 100. 0 100.0 
Carrot Danwersihalilonoeesemercc eee eseerieeeeree cick cee cme. 74. 0 66. 0 88.0 69.0 
Corn, NA Qe fears alanis one ea eSeiae Minas SE ie ce ws steel gi eereicie 99.5 100. 0 99.5 100.0 
Mbp ole ls 1B}. CUE ecodco nee ae eens GOCE SSO SH ae eeCs eaten 94.0 94.5 91.5 93.5 
Muskmelons Bunrellisig emia yee se mise ne cise ieee cceiceiee 64.5 73.0 70.0 64.0 
Onion-PAUstraliangyrowieeesesese sea eee eee eace se eee 54. 0 53.0 40.5 57.5 
iRadishe Ss carletclobess: salen eee ee eee nS Sa Pesce 98.5 94.5 94.5 91.5 
HA DCMNOS Obl meses jace fe cee ee et eee ere Alea 92.0 83.5 92.0 78.0 
IRICC ELON GULAS eee eee ae eee eee seine chee ee ce sem cites ogee 89.5 95. 5 96. 0 96. 0 
Soyabean Blo rie see er 8 tee eee see selec cawekieueciale 75. 0 85. 0 76.5 81.5 
ARTA O LVN Op aya sre nes eee re a ieee eee ie AO oe 66. 0 81.0 92.5 86.0 
Nitieats Cbeicimes ete ere ae a SY ee 97.0 95.5 97.0 97.0 
Apparently chloropicrin stimulates the growth of rice and timothy 
and injures somewhat the seeds of alfalfa and radishes. The rest of 
the seeds showed no marked effects of the treatment. 
The results of a series of experiments on Fusarium, Ascochyta, 
Penicillium, and Colletotrichum indicate that chloropicrin can not be 
used as a fungicide. 
1 Moore, Fumigation with chloropicrin. J. Econ. Entomol., 11 (1918): 357-362. 
