- 16 - ' 
Mclr.&oo and Siegers ( 188 ) in I92U reported that a cold alcoholic 
'extract -of cube plus soap in water (1 + 2 + 100) killed 95 percent of 
this -species" "within 2k hours. The dry cute resin dissolved in alcohol 
and sprayed with 'soap in water (1 + 2 + 100) killed only 60 percent with- 
in 2 days. 
Watson ( 302 ) in 1925 wrote that "Derris oil" [Derrisol?] 1 table- 
spoon to a gallon of water was an effective dip for the control of the 
citrus aphid in Florida. The infested terminal growth was bent over into 
a bucket containing the solution. 
The Florida Agricultural Experiment Station ( 102 , 105 , IOU) re- 
ported in 1926 .that Derrisol was tried against the citrus aphid, in com- 
parison with nicotine sulfate. Its action was much slower but it seemed 
to have a repellent effect for a day or two. It did not penetrate the 
curled leaves so well as did nicotine sulfate. This station in 1931 re ~ 
ported that an extract of Tcphrosia virginiana - was ineffective against 
this species; and in its annual report for 193^ stated that good control 
of the green citrus aphid was obtained with a product containing 50 per- 
cent of white oil and 0.33 percent of rotenone. 
Fryer ( 108 ) in 1Q26 gave the following directions for the use of 
Derrisol: Derrisol should be diluted with water 1:10 and this solution 
then added to water to make a final dilution of 1 pint of Derrisol per 
100 gallons. The Derrisol should never be added directly to the water 
in the spray tank, 'as a dilution of uniform strength is difficult to 
obtain in this manner. Soap may be used with Derrisol, but its use is 
unnecessary. Derrisol can be used as a mixed spray with oil emulsion, 
lime-sulfur, bordeaux, and arsenates, care being taken that the Derrisol 
is added only to the diluted insecticides. It is most important not to 
add the Derrisol to the concentrated spray material when mixed spraying 
is desired, because some of the active ingredient may be thrown out of 
solution and the final efficiency of the spray mixture be thereby impaired. 
Derrisol was effective against the citrus aphid, andalso against aphids 
and other insect pests on hops and fruits in England. 
Lenfest (ISO) in 1926 mentioned Derrisol and Black Leaf Uo as 
about the two best contact insecticides for. use against citrus aphids 
in Florida. Derrisol spreads well without soap. Lime-sulfur mixed with 
Derrisol will kill rust mites and red spiders, as well as aphids. 
Miller ( 202 ) in 1929 reported tests to control the green citrus 
aphid in Florida. Derris extract at any of the ordinary spraying strengths 
was not toxic to plants. When used against aphids at 1 part .to 800 it 
gave a 99-P cr ccnt kill and at Ipart to 1,000 a 95-? Gr eent- kill.. This- 
insecticide, however, is a slow-acting material and will not kill all the 
aphids in 2U hours, but shows its real effectiveness in 36 to U8 hours. 
Miller was not able to find that derris extracts had any more lasting 
effect or repellent action than' nicotine sulfate. 
Tic-^ot and Thompson ( 269 ) in 1930 recorded the results of laboratory 
tests with nicotine, pyrethrum, and derris ^reparations made at Gaines- 
* r ille, Fla. Against the green citrus aphid, Feoton, 1-1/M- pounds- to 100 
gallons of water, plus Grandpa' s Wonder Spray, 5 pounds to 100 gallons, 
