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* 
standing. . The toxicity of derris extract varies with different 
specie? of insects. Derris extracts were more toxic to insects 
than were solutions of pure rotenone, although the concentra- 
tion of rotenone was practically the same in each case. Rote- 
, none alone is not an adeauate criterion to- evaluate the toxic- 
ity of derris root to insects. 
Farrar (93) in 193^ reported that tests made in Illinois showed 
that extracts of pyrethrum, derris, or cube were not so efficient against 
A. -oomi as was nicotine mixed with oil emulsion. The addition of soap 
increased the killing power of an oil containing such extracts, hut not 
enough to warrant the added cost of the extracts. 
Etablissements Rotenia in 193& reported insecticide tests against 
A. rjomi on apple and near trees (see discussion under A. papaveris , on 
p. S). 
The Wisconsin Agricultural Experiment Station ( 321 ) in 1939 re- 
ported very good results with an experimental derris dust applied at the 
rate of about 1 pound per. tree. The mixture was made up of 12 pounds 
of ground derris root (5 percent rotenone), 2U pounds of talc, 12 pounds 
of dusting sulfur, and 12 pounds of Goulac. Within a week after this • 
mixture was used practically all the aphids had been destroyed. The 
only.aphiis found were a few winged adults that a'O'oarently. had flown in 
from other trees, and some offspring of such insects. A dust made up 
of 10 rounds of Uo percent nicotine sulfate to 125 pounds of lime, so 
as to give about a 3 percent nicotine content, was also tested. When 
used at the rate of approximately 1/2 pound per tree, this material gave 
only fair control. Two days after treatment the nicotine-lime mixture 
seemed to be giving about as good control as derris, but a week after 
dusting the comparison was very much in favor of derris. 
Aphi s ruraicis L. , the bean aphid 
'Tclndoo, Sievers, and Abbott ( 189 ) i n 1919 reported that derris 
ponder, used as a dust under practical conditions, was effective against 
bean aphids. Mclndoo p.nd Sievers (128) in I92U reported cube powder to 
be effective against bean aphids, both as a dust and as an infusion. 
Fryer et al. ( 107 ) in 1923 used A. rumicis as one of the test 
insects to determine the insecticidal value of different samples of 
Derris elliotica roots. Aphids were less susceptible than were certain 
Gimlet te (120) in I923 reported work that H. E. Durham did with 
derris in 1903. Derris had no effect as a contact poison on A. rumicis . 
Tattersf ield and Roach ( 26k ) in 1923 referred to Durham' s work 
on derri= in which he found the bean aphid resistant to wet application. 
The Rothamsted Experimental Station ( 237 ) in I92U reported that 
