- g - , 
powdering; finally com/ple.ted, in a. neat grinder. The fine -oovrder was 
separated .fro. m the fibers, by lifting through -fine-meshed cloth. In the 
comparative studies of the' effect of various-concentrations, D. philip - 
p inensis was used because' it was relatively- 'mcrre abundant ,• hence more 
easily p ; ro curable t than the other?.' 'Te-stte vere made. on mqsouito larvae 
and on A. medicaginis . The concentratioTi 'o"f D. ynhilipninensis which 
"brought about the largest number of 'death's -of aphids was much higher 
than that reouired for mosouito larvae, •■namely, U:1,000. The lowest 
concentration of 33. philippinensis used, 0. 5*1,000, caused a notice- 
able percentage of mortality among aphids, as compared with the control. 
Gaines ( llU ) in 1939 reported tests against A. nedicagin is of 
derris or cube a.dded to fluorine compounds and applied a? dusts (see 
discussion under A. £ossyp_i_i, p. 6). 
Aphis nerii Jonsc. • ' 
A commercial derris extract at 11^00 gave 13 percent control. — 
DeOng and White (76) in 1924. - ■ 
Aphis odinae (van der Goot) 
The Mysore, India, Department of Agriculture (203) in 193^ report- 
ed suspensions and alcoholic extract? of derris to "be effective against 
this species. 
Aphis papa^eris 1 , 
Estahlissements Hotenia in 193^, in a letter to R. C. Roark, stated 
that this species on cherry trees is killed by a proprietary dust contain- 
ing 12 percent of cube of 6 percent rotenone. content . 
Aphis pomi De-^;. , the apple aphid, or green a^ple aphid 
Mclndoo, Sievers, and Abbott (189.) in 1919 reported that derris' 
powder used as a dust under practical conditions was effective against 
green apple aphids. 
Kelsall et al . ( 169 ) in 1926 reported that against the green apple 
aphid derris, 5 pounds in 100 imperial gallons of water, without soap, 
gave practically complete control, "being a little superior to 1 pound of 
nicotine sulfate (ho percent). With the addition of a little soap to the 
solution, derric-- as low as 2-1/2 pounds to 100 imperial gallons 'of "water 
ga Tr e 100-percent mortality, ^nd is superior to 1 pound of nicotine sul- 
fate (40 percent). A dust containing as high as 20 percent of derris 
plus SO percent of hydrated lime proved ineffective against the green 
apple aphid when applied to dry foliage. Derris dust requires moisture 
to make its toxic properties effective against this aphid. 
Outright (60) in 193Q reported that Derrisol was -the "best of the 
derris products tried against a"^ple aphids. The efficacy of lime-sulfur 
or oil sprays against aphid_ eggs was "but little improved by the addition 
of Derrisol, At l:g'po Derrisol satisfactorily killed aphids if they were 
thoroughly wetted. '. 
