Sept. 3, 1917 



Quassia Extract as a Contact Insecticide 



511 



Table VI. — Methods of preparing spray solutionis from quassiin powder with various 

 solvents and results of preliminary tests of these solutions on aphids in laboratory 



Experi- 

 ment 



No. 



Procedure. 



Excess of powder shaken in 

 ether, evaporated, and resi- 

 due extracted with water. 



Powder exhausted with ether 

 and undissolved portions 

 then extracted with water. 



0.1 gm. extracted with 500 

 c. c. of water for 2 hours 

 and diluted with water. 



0.1 gm. extracted with 1,000 

 c. c. of water for following- 

 periods: 



0.1 gm. boiled in 1,000 c. c. of 

 water for 2 hours and di- 

 luted with water. 



An excess of powder shaken 

 in distilled water for 5 hours. 



0.1 gm. extracted with 1,000 

 c. c. of soap solution for 

 following periods; 



o.i gm. boiled in 1,000 c. c. of 

 soap solution for 2 hours 

 and diluted with soap 

 solution. 



o.i gm. extracted with 1,000 

 c. c. of I per cent sodium- 

 carbonate solution for fol- 

 lowing periods: 



0.1 gm. boiled in 1,000 c. c. of 

 I per cent sodium-carbon- 

 ate solution for 2 hoiurs and 

 diluted with water. 



0.1 gm. extracted with 1,000 

 c. c. of I per cent lye solu- 

 tion for following periods: 



0.1 gm. boiled in 1,000 c. c. of 



1 per cent lye solution for 



2 hours and diluted with 

 water. 



Ether solvents, 

 dilutions, and 

 time of extrac- 

 tions. 



Ordinary ether 



A n h y d r ous 

 ether. 



A n h y d rous 

 ether. 



Ordinary ether 



A n h y d r ous 

 ether. 



A n h y d r ous 

 ether. 



No dilution 



No dilution. 

 No dilution. 



Dilution 1:5. 



I hour 



3 hours 



5 hours 



24 hours 



No dilution.. 

 Dilution 1:5. 

 No dilution.. 



I hour . 



Species of aphids. 



Aphis rumicis. 

 do 



Macrosiphum pisi 



Aphis rumicis . 

 do 



Macrosiphum pisi. 



Macrosiphum. liri- 



odendri. 



do 



Chaitophorus pop- 



ulicola. 

 Macrosiphum liri- 



odendri. 



....do 



....do 



....do 



....do 



....do 



....do 



....do 



Num- 

 ber of 

 aphids 

 used. 



3 nours 

 5 hours 



24 hours I do 



No dilution.. do 



Dilution 1:5 do 



Aphis sp 



Macrosiphum liri- 

 odendri. 



....do 



....do 



Dilution i : 10. . 

 'dilution 1 : 50. . 

 Dilution i : 100. 



I hour 



3 hours 



5 hours 



24 hours 



.do. 

 .do. 

 .do. 

 .do. 

 .do. 

 .do. 

 .do. 



No dilution do. 



Dilution 1:5 do. 



I hour 



3 hours 



5 hours 



No dilution . 



.do. 

 .do. 

 .do. 

 .do. 



104 

 62 



105 

 129 



508 



335 



16 

 36 



31 

 114 

 277 

 300 



46 



46 

 21 

 294 

 III 

 61 

 29 

 30 

 31 

 40 

 37 



54 

 128 



lOI 



Results. 



Per- 

 centage 

 killed. 



100 

 95 



82 



100 



90 



100 



100 

 100 

 100 

 100 

 100 



ICO 



100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 



100 

 100 

 100 

 100 



Mini- 

 mum 

 time re- 

 quired 

 to kill 



per- 

 centage 

 indi- 

 cated. 



Hours. 

 8 

 7 



2'A 



Reference to Table VI shows the following: The ether- water extract 

 (probably mostly quassol) of impure quassiin powder killed about one- 

 half of the aphids tested (experiment i), while the practically pure 

 quassiin killed 92 per cent of those sprayed (experiment 2). Generally 

 speaking, all of the remaining extracts were efficient within a few hours. 

 In all but one case it is indicated that boiling slightly increases the 

 efficiency of the extracts. Had they been boiled longer than two hours, 

 this indication might have been reversed. Boiling quassiin powder 



