-47- 
or acetone against a hot plate (400° C.) ^s very toxic to house- 
flies. An oleo-resin containing 25 percent of pyrethrins, alone 
and in combination with rotenone, also gave very good results. 
This method of application of rotenone has many advantages over 
other methods: (l) The smoke containing rotenone is very stable; 
(2) it is not readily adsorbed on surfaces such as wells or floors; 
(3) it has high efficiency in respect to amount of material used 
and amount of solvent required; (4) it is probably less dangerous 
to the health of j^lants; and (5) it is easily confined, as compared 
with most other fumigants. 
Allen and Erooks (9) in 1940 reported the results of a detailed 
study of the effect of alkalinity on rotenone-bearing dusts made 
by testing kerosene extracts of the dust mixtures on houseflies. The 
diluents tested ranged in pH from 4.23 for calcium sulfate to 12.5 
for hydrated lime. Pondered derris, timbo, and barbasco were mixed 
^ith the diluents in the ratio of 1:9. It was concluded that rotenone 
-bearing dusts -prepared from highly alkaline diluents, and kept in 
daiTvo storage without light for 7 days, exhibited little or no change 
in pH, but showed considerable loss in toxicity when used in kerosene 
extracts in tests with houseflies. Parallel sanvoles of acid dust, 
kept under identical storage conditions, retained their toxicity. 
Dry or unmoistened alkaline and acid samples remained unchanged.. The 
addition of sulfur to the alkaline dust mixtures prevented deterior- 
ation of the rotenone-bearing dust mixtures under the conditions of 
this experiment. 
Goodhue and Sullivan ( 119 ) in 1940 reported on toxicities to the 
housefly of smoke from derris and pyrethrum. The effect of the smoke 
from a burning mixture consisting of 50 percent, of derris, 30 percent 
of cornstalks, and 20 percent of sodium nitrate w as tested against 
the housefly. The tests were made by exposing the flies in cages in 
a Peet-Grady chamber for 1 hour at 25° to 29° C. Derris smoke was 
more than 10 times as toxic as the smoke from pyrethrum burned in 
the same way. The presence of rotenone in the smoke, even after 1 
hour, "s:s demonstrated by the Goodhue red-color test. The derris 
mixture at 4 ounces per 1,000 cubic feet killed 95 1*1.7 percent of 
the flies in 72 hours. 
Mironoff et al. ( 206 ) in 1940 reported tests with derris against 
the housefly. The mortality was about 97.6 percent when pyrethrum 
was used in dosages of 2 gm. in 1 cubic meter, whereas derris geve 
97.8 percent kill under the same conditions, with only one- twentieth 
of the dosage used for pyrethrum. The action of derris is slower 
than that of pyrethrum. The paralysis caused by derris is fetal 
to the fly, whereas the paralysis caused by pyrethrum does not 
always result in a kill. 
Sievers et el. ( 250 ) in 1940 reported on the changes in the 
insecticidal value of the roots of cultivated devil's—shoestrings 
at 4 seasonal growth periods. For the toxicity tests made on the 
housefly by the methods of Campbell and Sullivan, acetone extracts 
