14 BULLETIN 1313, U. S. DEPARTMENT OF AGRICULTURE 
effect on the eggs. About half a pint per 1,000 cubic feet should be 
used, and the fumigation should be continued for not less than 18 
hours. Lloyd states that: 
It has been used for a wide variety of plants, including tomatoes, and no 
damage has resulted except in one case when the foliage of three young sycamores 
(Acer pseudo-planatus) * growing in pots turned brown the day after the fumi- 
gation and was subsequently shed. 
Speyer (23) also found tetrachloroethane effective against adult 
white flies, but its effect on the red spider was only temporary. 
The tetrachloroethane, when used at the rate of 10 ounces per 
1,000 cubic feet, severely injured several varieties of chrysanthemum. 
Richardson and Smith (21) found that 34 and 31 grams per 100 
cubic centimeters of chloroform and carbon tetrachloride, res- 
pectively, were necessary to kill aphids, and that the tolerance of 
the nasturtium plant for these two compounds varied from 5 to 8. 
Chlorobenzene and commercial trichlorobenzene were less toxic to 
aphids than carbon disulphide, and their toxic concentrations ex- 
ceeded the tolerance of the plant. 
Moore (14, 15) used chlorobenzene, p-dichlorobenzene, chloroform, 
carbon tetrachloride, and chloretone (trichloro tertiary butyl 
alcohol) in various tests on flies. 
FLUORIDES 
Fluorobenzene at a concentration of 1.9 per cent showed 100 per 
cent mortality against Srtophilus oryza, but difluorodiphenyl ex- 
hibited almost no toxicity, owing probably to its slight volatility at 
the temperature of the test. 
Organic fluorine compounds have not been tested by many investi- 
gators, probably because they are rare and expensive. 
IODIDES 
The only iodide tested, normal butyl iodide, killed all the weevils 
at a concentration of 0.8 per cent. 
Moore (/4) found iodebenzene to be more toxic to house flies than 
the corresponding bromine and chlorine compounds. 
Tattersfield and Roberts (24) found iodoform to be nontoxic to 
wireworms, while iodobenzene was moderately toxic. 
According to Holt (9), cockroaches dusted with iodoform did not 
succumb until a period of 9 hours had elapsed. 
ALCOHOLS AND PHENOLS 
Methyl alcohol was more toxic than ethyl alcohol, but with this 
exception the toxicity increased with increasing molecular weight 
through isoamyl alcohol. Thymol, menthol, and geraniol are so 
slightly volatile at ordinary temperature as to be practically nontoxic. 
Richardson and Smith (2/) found meeiay ethyl, n-propyl, 
n-butyl, capryl, isoamyl, benzyl, and furfuryl alcohols to be ineffective 
against aphids. Even pure methyl and ethyl alcohols killed less 
than 95 per cent of the insects. 
Moore (15) found the toxicity of methyl, ethyl, and amyl alcohols, 
menthol, and thymol on house flies to increase with decreasing 
volatility. 
Trillat and Legendre (26) showed that methyl, ethyl, propyl, and 
amyl alcohols had only a feeble toxicity to mosquitoes. ~ 
4Sycamore maple. 
