- 15 - 
and 0.1 percent of the root, the percentages of moribund and dead insects 
recorded on the third day after spraying were 95 and 50 percent, respec- 
tively. The root thus shov/s a decided toxic action to this insect. 
Foliafume (a pyrethrum-derris spray with spreader) at 1:^00 killed 
88 -nercent in U8 hours. — Peni.ck and Company ( 225 ) in 193&- 
Van der Vecht ( 288 ) in 1937 tested the method of Jones and Smith 
(165), usi^e the results obtained by Tat ters.fi eld and Martin with differ- 
ent specie's of derris against A. rumicis* . This method gives good result? 
in evaluating derris containing more than k percent of rotenone; the 
toxic valve of Derris rial ace en? is (containing from to 2.7 percent 
rotenone) is best expressed by the formula: Value = rotenone content + 
1/3 remainder of extract. 
Craufar&rBenson (52) in 1938 experimented with field-collected 
A. rumicis , but results were completely unreliable. These aphids were 
also reared in a greenhouse under standard conditions and used for lab- 
oratory testing of liquid contact insecticides, especially derris prepa- 
rations. The results of trials on any one day were comparable and indi- 
cated the comparative toxicities of the insecticides tested, but when 
the same insecticide was tested on different days the results were in- 
coordinate. 
©under son ( 13^ ) in 193^ recommended derris against bean aphids. 
Howes ( 156 ) in 193- reported tests made at the Rothamsted Experimental 
Station on insects [presumably the bean aphid] with alcoholic extracts 
of the roots of Tephrosia macropoda cultivated in ITatal. A concentration 
of 0.25 percent of a 2-year-old root killed 100 percent of the insects. 
Tattersfield and Martin ( 263 ) in 1938 reported on the toxicity to 
the bean aphid of certain products isolated from derris root. The tox- 
icities to A. rumicis of rotenone, toxicarol precursor, sumatrol, toxi- 
carol, and the residual resins from the Sumatra- type and Derris elliptica 
roots were determined. The toxicity in descending order was rotenone > 
■&• elliptica resin > Sumatra-type resin > sumatrol = toxicarol precursor > 
inactive toxicarol. Rotenone was 6 times as toxic as the Sumatra-type 
resin, h times as toxic as that derived from D. elliptica , and from 13 
to 15 times as toxic as the toxicarol precursor. 
Aphi s sambuci L. , a black aphid 
Derris or rotenone suspensions at a concentration of 1:5000 or 
1:6250 were effective. — DeSussy et al. (32), in 1935 . 
Aphis spiraecola Patch, the spirea aphid, or. green citrus aphid 
Mclndoo, Sievers, and Abbott ( 189 ) in 1919 reported that an alcohol- 
ic extract of derris added to ^ater at the rate of extract fron 1 pound 
of powder to 100 gallons of water, plus 2 pounds of fish-oil soap, killed 
only 30 percent of this aphid. When derris powder was soaked in soap 
solution 2 days and the mixture sprayed, 50 percent of the anhids were 
killed. 
