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earth killed 100 percent of these aphids on nasturtium in a greenhouse. 
Racemic deguelin killed 100 percent at 1:10,000; tephrosin 100 percent 
at 1:5,000; and toxicarol 9^»5 percent at 1:500. 
Shepard, using the bean aphid as the test insect, noted that in 
acetone or in alcohol rotenone decomposes only very slowly, hut in 
aqueous suspensions made from these solutions it suffers a loss in toxi- 
city on standing. — Davidson and Jones (65) in 193 1 * 
Shepard ( 2Ul ) in 1931 tested the relative toxicity of rotenone 
and nicotine to the "bean aphid. The rotenone was first dissolved in 95 
percent alcohol (0.25 gm. in 100 cc). It was found necessary to warm 
the mixture somewhat in a water bath to dissolve the rotenone entirely. 
On dilution with distilled water a stable millcy suspension resulted. 
Colonies of A. rumicis on nasturtium plants were sprayed with the various 
dilutions. Both rotenone and nicotine were tested in duplicate at the 
same concentration on the same day, all the tests being made within as 
few days as possible. The spray mixtures were made fresh each day. 
Saponin at 1-percent concentration was used as spreader, the reouired 
amount of stock solution of 5- to 10-percent saponin being added after 
the rotenone suspension was diluted somewhat with water. At concentra- 
tions of 0.001, 0.01, and 0.02 gm. per 100 cc. rotenone was more toxic 
than nicotine. Rotenone sprays prepared from acetone and alcohol stock 
solutions were equally toxic against A. rumicis . A suspension of rote- 
none (0.01 percent) in 0.01 normal sodium hydroxide when fresh killed 
71.2 percent of bean aphids, as compared with 3^.7 percent at the end of 
8 days. In distilled water the drop in mortality was from 93*^ to 79«9 
and in 0.01 normal sulfuric acid from 93*9 to 67. percent in the same 
time. Acid caused a clotting of the rotenone particles. Cube extract 
in potassium oleate at 1:50,000 killed 9^*5 percent of A. rumicis , but 
after standing 18 days the kill at 1:60,000 dropped from 76. 1 to U6.7 
percent, indicating deterioration of the cube extract within this time. 
Cube extract in oil emulsified in water with a sulfonate emulsifier 
(cube 1:200,000 and oil 0.5 percent) killed. 80. 3 percent of bean aphids, 
whereas the oil alone killed 18.5 percent. 
G-arman ( 117 ) in 193^ reported laboratory and greenhouse tests of 
commercial extracts of derris and of cube against the bean aphid on nas- 
turtiums. Five commercial rotenone preparations and two commercial 
pyrethrum-rotenone combinations were tested. It was found that the rote- 
none or pyrethrin content of these preparations must be increased if they 
are to compare favorably as aphicides with nicotine and anabasine products, 
Gimingham ( 119 ) in 193^ described recent work on insecticides in 
Great Britain. Several species of the genus Tephrosia showed marked- in- 
secticidal properties against aphids [probably A. rumicis ] , the leaves 
and seeds of T. ■"•ogelii , the roots of T. toxicaria , and the roots and 
stems of T. mac r op da. all yielding highly toxic extracts. Extracts of 
white and black haiari ( Loncho carpus spp.) from British Guiana proved 
highly toxic to aphids. 
The bean aphid' was used as a test insect by Badertscher and Wother- 
spoon (11_) in 1935 in testing the decomposition of derris and pyre thrum 
powders when exposed to the light from a Uviarc mercury-vapor lamp. An 
