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Pnylla sp, 
Carlos ( 47 ) in. 1926 reported that Psylla is one of the chief 
insect peeve that car. be easily exterminated by the application of 
insecticides containing derris or its products. 
An anonymous vritcr (2) in 1950 repcrxrd the aqueous extract -of 
derris root to be effective against £.syliids. 
Worsley (324) in 1336 reported concerning bark of Lluhdulea suberosa 
Berth. (0.9 percent rotenone) fro;. 1 Lioa district, Tar: yi a Territory, 
East Africa, and derris root (5,4 percent ro ten one)", that the follovdng 
concentrations are required to kill 100 percent of a species of Tayl la 
infe : L: ; citrus in Amanis 0,45 percent of Fundi.'; lea bark, 0.S5 percent of 
derris root, and 0.25 percent of nicotine. 
Psyllids on pear trees v. r ere killed by a proprietary dust con- 
taining 12 percent of cube of 6 percent rotcnone contort, according to 
a letter to R. C. Poark from Eta'bliss omenta Rotenia in 1938. 
