FUMIGATION AGAINST GRAIN WEEVILS 19 
quinoline, quinaldine, and piperazine. The minimum toxic concen- 
tration of pyridine was 25 grams per 100 cubic centimeters of solu- 
tion. None of these compounds was more than one-hundredth as 
effective as nicotine. 
McClintock, Hamilton, and Lowe (13) found little difference in 
the toxicity of pyridine, pyridine bases, and quinoline for bedbugs, 
cockroaches, house flies, disthes moths, and mosquitoes. 
Jewson and Tattersfield (10) found pyridine effective against mites. 
Lefroy (11) found that quinoline and pyridine killed some of the 
mealworms dipped in the liquids, but that a 1 per cent aqueous 
solution of nicotine killed none. 
Tattersfield and Roberts (24) found that pyridine was moderately 
toxic against wireworms. 
Moore (15) found pyridine somewhat more toxic than its position 
in the table of organic compounds arranged according to volatility 
would indicate. Its toxicity was about the same as that of furfural. 
INORGANIC COMPOUNDS 
None of the inorganic compounds tested proved suitable as a 
fumigant. Thionyl chloride killed all weevils at a concentration of 
4.5 per cent; concentrations of carbon dioxide ranging from 50 to 100 
per cent were required to effect a complete kill. 
RELATION BETWEEN VOLATILITY AND TOXICITY OF FUMIGANTS 
The compounds causing 100 per cent mortality to S. oryza (selected 
on account of its high resistance to fumigants) exposed to them for 
24 hours, together with their boiling points, are listed in Table 3. 
TABLE 3.— Toxicity of fumigants to Sitophilus oryza (arranged in order of decreasing 
effect) 
peer Minimum 
- tion caus- Boiling pee wo Cost per Cost per 
Fumigant ing 100) per point i per cent pound 2 PROD GEEAG 
tality in 24 mortality, 
nouns in ours 
Lbs. per 
| Per cent OF 1,000 cu. ft.| Dollars Dollars 
IE ypicnlorohyarin= 2-22 =. 222 oe eee * 30.09 116. 6 0. 23 27. 22 6. 26 
iPhenylacetonitriles 2 sem. oS . 10 2315.0, 33 18. 14 5. 99 
Chloroacetophenone----_------------------- . 10 247.0 43 9. 07 3. 90 
WWiethyiihOCyan ales wns oe te STO 133. 0 20 Die2e 5. 44 
ACE LO DHE ONG Meise Spices eat 2 oe be om 5 3.16 202. 0 . 54 5. 90 3. 18 
ChiorgorcelOue en es Se OAs AE eee BIEL . 26 119. 0 .67 27. 22 18. 24 
IBen7ZaldehyGGe 28.5 ete ee ee Fy ee | 3.27 178. 3 . 80 1G aie? . 90 
AIVISOTHIOCYaNaAleL 2952-22 a 3 34 150. 7 . 94 4.08 3. 84 
Crovouakdenyvdes ss -se 1s oe Peel ere y 3 50 104. 0 eB fetal ch 8 hh re rer ae 
EEhylene-OEOmid es see tee E: . 50 129. 0 2. 62 .91 2. 38 
PSODIGpyeMlOL Males ean eas Shean en 3. 50 70. 0 1. 23 ZED, 2.79 
UMOSTE WRI GO: =. Sx teriie sel ts 92s ech 250 130. 0 1. 50 13. 61 20. 42 
Jsoamvliniguiteses= = 2 Se ee 3.60 99. 0 1. 96 9. 07 17. 78 
EC hytonimatesct dose 24s Se Bee . 60 54. 4 1. 24 . 40 . 50 
(TreLSy PAIR 0071) 2 1 2 ee ie . 60 75. 0 TZ 3. 63 6. 24 
UALB\D UNA CAO It T(c\o Be & ORT ae Perky a ae eee ee Ee Oem are . 60 76. 6 |. 122 36. 29 44, 27 
Methyl cyano formate: =. 22-2222... . 68 100. 0 TU (Sf bet i Pie pacientes 
Fropy ene CYCh OF ee. ee ae eee ae sae 96. 8 2. 20 1. 27 2: a 
PING Bhae eee a SA AAMT Od Fa) IE . 80 161. 0 2.14 B20 A) 
Anichlergebhane =: Shee. 27 lt ate ie ee oT . 80 74. 1 2.97 PAH 6. 74 
poo! Been A NE aS eS ee ee . 80 131. 0 1, 96 * ee es “ie 
Tia iVAOGIGG tS sees ee a ee . 80 129. 9 4.10 . 07 7.1 
iy GnOGyanale! 1 ee ee oe . 80 146. 0 1, 94 22. 68 44,00 
EVEL Gare eet eer) ee os SERA RL eee . 83 116. 0 1. 83 . 36 . 66 
1 Boiling points taken from Beilstein. u 
2 Most of the prices are taken from List No. 10 of the Eastman Kodak Co., Rochester, N. Y., issued 
September, 1923; some arefrom wholesale quotations by the Oil, Paint, and Drug Reporter, March 3, 1924; 
and some are quotations from the Miner Laboratories, Chicago, Ill. 
3’ Minimum concentrations tested. 
