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toxicaria. and T. vcgelii were resinous. Crystals closely corresponding 
to tephrosin, as isolated by Hanriot, were less toxic. 
Tattersfield and Giningham ( 239 , 26o ) in 1927 referred to their 
previous work with white and "black haiari and stated that the tuba.toxin 
(rotenone) these plants contain is unauestionably one of the most potent 
insecticides. The toxicity to the "black "bean aphid of products isolated 
from haiari, compared with nicotine, is shown in graphs. In 193 2 they 
reported that samples of roots, stems, and leaves of Derris scandens from 
British G-uiana and "branches, roots, and leaves of D. trifoliata ( uliginosa ) 
from India and Siara showed little or no toxicity to "bean aphids. 
In preliminary trials the plant material was ground fine, extracted 
with alcohol or water, and the extracts diluted with a 0.5 percent solution 
of nontoxic saponin. A high concentration (equivalent to 1 to 5 percent 
of the "olant material) was tried first. The insect used in most of the 
experiments was A. rumicis , feeding on broadbean plants, and bred, so 
far as possible, under standardized condition?. The alcohol or aqueous 
extracts of Tephrosia Candida , T. purpurea , T. heckmanniana , and T. hook - 
eriana showed little or no toxicity. The seeds of T_. hookeriana showed 
some toxicity. The alcoholic extracts of the roots, and to a less extent 
of the stems, of T. macropoda from ITatal possess considerable contact- 
insecticidal value. The leaves are of little value. The bark of Millet - 
tia pachycarpa Benth. was not toxic, but the alcoholic extracts of stems, 
seeds, and peds of Mundulea suberosa Benth. from India showed definite 
activity as contact insecticides. One specimen of the seeds and pods 
of Loncho carpus latifolius from Trinidad showed slight toxicity. 
A. rumicis is not appreciably controlled by sprays of derris which, 
according to Durham (91_) in 1926, is essentially a stomach poison. In 
an insectary experiment it was killed completely but slowly by derris, 
5 pounds to 100 imperial gallons of water, according to Kelsall et al. 
( 169 ) in 1926. 
Neoton (derris extract in fish oil), 197.5 g™* plus an equal 
weight of soap in Uo imperial gallons of water, killed from 50 to 100 
nercent of bean ar>hids. — Institute of Physical and Chemical Research 
(I62) in 1927. 
Turner ( 271 ) in 1932 reported the results of work carried on dur- 
ing 192g to 1931, inclusive, with cube extract and with rotenone obtained 
from cube. 
Davidson (6^, 6U-) in 1930 reported the following results of tests 
of aoueous suspensions of t>ure rotenone upon the bean aphid: 
Concentration Mortality 
(gm. :cc.) (percent) 
1:100,000 99-5 
1:200,000 100.0 
1:300,000 97.0 
A dust composed of 2 t>arts of rotenone and 98 parts of diatomaceous 
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