- 6 - 
fro.! De^is elliptica roots in the ratio of 1 pound of roots to 200 gallons 
of water plus 4 pounds of fish-oil soap killed 100 percent of this aphid 
in laboratory tests. Extracts of several species of Derris were tested, 
as well as a derris dust which killed 99 percent. 
Dennis (JJ, jffi;) ^ United States Patent 1,621,240, issued March 15, 
1927, and in Reissue IS, 667, issued Fove.mber 22, 193^, stated that an 
alcoholic extr?ct of cube is eight times as effective as' similar derris 
extract and is also slightly more effective than nicotine sulfate when 
sprayed on the cotton aphid. _ ■ 
When A. gossypii on celery in a greenhouse was dusted with a mix- 
ture of 2 r>arts of rotenone and 92 parts of diatomaceous earth, 68.9 per- 
cent '-'ere killed. — Davidson ( 63 ) in 193^- 
Little ( 183 ) in 1931 gave a detailed account of the insect'icidal 
properties of devil 1 s- shoestring ( Tenhrosia virginiana ) . Dried and powdered 
(100-mesh) roots were suspended in water and tested against many kinds of 
insects. When sprayed on A. gossypii at a. dilution of 1:3,200 without 
spreader, devil' s- shoestring gave a kill of 6U.3 percent, as compared with 
82.2 percent for nicotine sulfate and 73*1 percent for 1 derris. 
Field tests by Little ( 182 ) with A. gossypii showed that devil' s- 
shoestring has considerable promise as a contact spray. 
This insect is easily controlled by spraying with Derrisol at 1:800 
or Katakilla at 5 pounds per 100 imperial gallons. — Andrics (10) in 1932. 
G-off and Tiseot ( 129 ) i n 1932 reported that the melon aphid may be 
controlled by treating the infested plants with one of the liouid aphi- 
cides containing extracts of nicotine, pyrethrum, or derris. 
Merino and Dtanes ( 197 ) in 1937 recommended a derris- soap spray 
for the control of this species on cotton in the Philippine Islands. 
"..'ille, Ocampo, Weberbauer, and Schofield ( ^07 ) of the Agricultural 
Experiment Station at Molina, Peru, in 1937 reported that sprays of c'dbe 
extract containing 0.05 or 0.01 "oercent of rotenone proved as effective 
against this species as a 0. 5-percent solution of nicotine sulfate. 
Gunderson ( 13^ ) in 193& recommended the u<-e of derris against melon 
aphids. 
Gaines ( 11^0 in 1939 reported the tests of derris or cube added to 
fluorine compounds and applied as dust^. 
Relative 
Treatment a-chid -oo^ulation 
Calcium arsenate 100 
Synthetic cryolite alone 100 
Synthetic cryolite + derris 
(0.5 percent rotenone) 14 
Barium fluosilic-te alone 103 
Barium fluosilicate + derris 
(0.5 percent rotenone) 23 
