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Coccus pseudomagnoliarum (Kw»), the citricola scale 
The California Fruit Growers' Exchange, Bureau of Pest Control (37), 
in September 1937 reported that fumigation tests showed the citricola 
scale to he resistant to hydrocyanic acid gas, as in the past. Orchards 
vrith any noticeable amount of this scale should be sprayed with light- 
medium oil. Growers desirous of reducing 'the use of oil to a minimum might 
well consider the derris-oil combinations, 
LaDue (179) in 1938 reported that in the early part of 1937 labora- 
tory experiments vere made using methyl isobutyl ketone, methyl-n-amyl 
ketone, and 2, ?J -dichloroethyl ether as intermediary solvents for the 
derris resir.ate and tank -mix spray oil. The derris resinate-methyl-n- 
amyl-ketone-oil mixture has been tested on C_, p s e ud oma gno 1 i a rum , The 
results indicated an added toxicity of the oil to this insect, A paste 
formed by the addition of methyl-n-amyl ketone or 2, 2* -dichloroethyl ether 
to the derris powder seemed to increase the efficiency of the material. 
The Exchange also reported (45, 46) in 1939 that cil-rotenone sprays at 
3/4 to 1 percent of medium oil were effective for control of mixed popu- 
lations of citricola scale and the black scale (§aissetia oleae (Bern.)), 
Coccus viridis (Green) 
Bhatta and Parayanan (15) in 1938 reported the v;ork done in Mysore 
on the insecticidal value of pTar.t fish poisons and other forest products. 
Alcoholic extracts of seed of Tephrcsia Candida, bark of Mundulea serice a 
(suberosa), seeds and leaves of Teph rosia villosa, and roots of" De rris 
elliptica at a concentration of 10 percent in most cases, but much less 
for the seeds and derris, gave from 60- to 100-percent mortality of 
(Lecanium) Coccus vir idis Green in 3 to 4 days, in "which period the 
standard insecticides, nicotine sulfate, and hongay, Pongamia glabra , 
oil-resin soap, both at 2 percent, gave from 80- to 100-percent mortality. 
In small-scale .field trials, extracts of seeds of Tephr osia Candida and 
stein bark of Lundulea seri cea v:erc effective at 2- and 3- percent concen- 
trations, respectively, against C, viridis on coffee and guava. Water 
suspensions and alcoholic extracts of derris (7 percent rotenone and 22 
percent ether extractives) were effective against Coccus ( Lecanium ) v iridis 
Green,— rL-ysore, India, Department of Agriculture (203) in 1938. 
Dactyl coins sp, 
Schmitt (240) in- 1930 reported derris dust to be ineffective against 
cochineal insects, 
Diaspis carueli Targ,, the juniper scale 
Hamilton ( 156 ) in 1938 reported cube and derris powders (4 percent 
rotenone and 16 to 18 percent total extractives) applied as a spray at 
the rate of 4 pounds per 100 gallons, with the addition of 4 pounds of 
rosin-residue emulsion, to be satisfactory contact poisons against young 
scales on juniper trees, 
S^ray with cube or derris powder (4 percent rotenone) at 4 pounds 
per 100 gallons, plus 4 pounds of rosin-residue emulsion, for the control 
of young scales. — Haude (144) in 1939. 
