- 17 - 
gave a mortality of 92. k percent. Most a'phids that, survived vrere inside 
curled leaven. ITeoton at the same concentration, plus Octagon laundry 
soap, 2-l/2 rounds to 100 gallons, gave a mortality of 81.9 percent, and 
plus 5 pounds Octagon laundry soap, a mortality of yk.k percent. Feoton 
at 2-1/2 pounds per 100 gallons, plus Octagon laundry soap, 5 pounds per 
100 gallons, gave a mortality of 96.2 percent. The highest kill (92. 8 
percent) in this series of tests was obtained with 50 percent of free 
nicotine at 1:1,000 plus 0.5-percent Penetrol. Reference to these results 
was made "by Thompson ( 267 ) "before the Florida State Horticultural Society 
at its 1930 meeting. Derrisol also was stated to give good control. 
Barley (S2) in 1931 reported laboratory tests using this species. 
Rotenone at 1:100,000 as a contact spray compared favorably with nicotine 
at 1:10,000 and pyrcthrins at 1: 7^,800 wrth Penetrol (1:200) in each spray. 
Hamilton and G-eramell ( 137 ) in 193^ compared the effectiveness of 
derris., pyrethrum, and hellebore powders against different insects. Dusts 
containing derris root powder (air-floated, U percent rotenone), pyreth- 
rum powder (l.l6 percent pyrethrins), mixtures of derris root ponder, 
pyrethrum powder, and hellebore powder (0..8 percent active principle) 
were tested. Inert clay was used as a diluent. Laboratory tests vrith • 
A. spiraecola showed that diluted derris powder (rotenone, 1 percent), 
pyrethrum powder, or mixtures of the two were effective, but hellebore 
was not effective. Derris powder appeared to be more effective when 
mixed v;ith water and applied as a spray, whereas the pyrethrum was more 
effective when applied as a dust. [Mixtures of derris and pyrethrum pow- 
ders were slightly more effecti'-e when applied as dusts than when applied 
as sprays.] 
Farrar (98) in 193& reported that extracts of pyrethrum, derris, 
or cube were not so efficient against A. spiraecola as nicotine mixed 
with oil emulsion. The addition of soap increased the killing power of 
an oil containing such extracts, but not enough to warrant the added cost 
of the extracts. 
Aphis tavaresi DelG. , an orange aphid 
Easily controlled by Derrisol 1:800 or by Katakilla 5 pounds per 
100 imperial gallons of water'. — Andries (10) in 1932. 
'iorslcy ( 32U ) in 193^ reported that bark of Mundulea suberosa Benth. 
(0.9 percent rotenone) fro r n Moa district, Tanganyika Territory, East 
Africa, was almost equal to derris root (5-^ percent rotenone) in toxicity 
to this aphid. Concentrations necessary to give 100-percent kill of A. 
tavaresi vrere 0.25 percent for nicotine, 0.29 percent for derris root, and 
0.33 percent for Mundulea bark. 
Bhatta and Harayanan (15) in 1937 stated that in small-scale field 
trials extracts of seeds of Tephrosia Candida and of the stem bark of Mun- 
dulea sericea vrere effective at 0.25- and 0.5-percent concentrations, re- 
spectively, against A. tavaresi on citrus. 
Y?n der Vecht (288) in 1937 tested the method of Jones and Smith 
( 180 ) using the results obtained by Vorsley with different species of 
derris against A_. tavaresi . This method gives good results 
