PLANTS — INSECTICIDAL PROPERTIES. 



15 



Table 2. — Comparative results obtained by dusting aphids with various 

 powders — Continued. 



Sample 



No. 



103 

 110 

 501 



521 

 522 

 503 

 110 

 501 



503 



501 



501 



103 

 110 



Species and preparation. 



Aphis sp. A: 



Pyrethrum 



Denis 



"Cube" 



Macrosiphum sp. A: 



Hura crepitans l 



D02 



Pyrethrum 



Denis 



"Cube" 



Macrosiphum sp. B: 



Pyrethrum 



Macrosinhum solanifolii: 



-Cube" 



Aphis rumicis: 



"Cube" 



Macrosiphonella sanbomi 



Pyrethrum 



Derris 



Esti- 

 mated 

 number 

 of indi- 

 viduals 



100 

 100 



100 



500 



500 



1,500 



1,000 



1,500 



100 



300 



200 



1,000 

 500 



Num- 

 ber of 

 sets. 



6 hours. 1 day. 2 days. 3 days 4 days 



Percentage of aphids dead within- 



100 

 99 



100 

 100 



100 

 100 



100 

 85 

 83 



97 



100 



1 No. 200 nowder of bark. 



No. 200 powder of sawdust. 



Table 3. — Comparative results obtained by testing various powders against 

 aphids in the form of fumigants, decoctions, infusions, and hot-tatter ex- 

 tracts. 



Sample 

 No. 



56 

 502 

 103 

 110 

 501 

 113 

 103 

 110 



56a 

 301a 



35fa 



502a 

 103a 



110a 

 501a 

 103a 



110a 

 50la 



103b 



103b 

 110b 

 110b 

 501b 

 501b 



501c 

 501c 



Preparation and how 

 used. 



Fumigant: 



Sabadilla burned . 

 Hellebore burned 

 Pyrethrum burned 

 Derris burned. . . 

 "Cube" burned. 

 Sabadilla burned 

 Pyrethrum burned 



Derris burned 



Decoction not filtered : 

 Sabadilla sprayed 

 Chinaberry 



sprayed. 

 Ami an t hium 



sprayed 



Hellebore sprayed 

 Pyrethrum 



sprayed. 

 Derris sprayed. .. 

 "Cube" sprayed. 

 Pyrethrum 



sprayed. 

 Derris sprayed . . . 

 "Cube" sprayed. . 

 Water extract (decoc- 

 tion filtered): 

 Pyrethrum 

 sprayed. 



Do 



Derris spraved . . . 



Do 



"Cube" sprayed. 



Do 



Infusion not filtered: 

 "Cube" sprayed. 

 Do 



Insects tested. 



Esti- 

 mated 

 number 

 of indi- 

 viduals. 



100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 



100 

 100 



100 



100 

 100 



100 

 100 

 100 



100 

 100 



100 

 100 

 100 

 100 

 100 



200 

 600 



Num- 

 ber of 

 sets. 



Species. 



Macrosiphum sp . C . 



do 



do 



do 



do 



M vzus persicae 



do 



do 



Aphis sp. B. 

 do 



.do. 

 .do. 



do 



do 



Aphis sp. A. 



do 



do 



.do. 



Aphis sp. B. 



do 



Aphis sp. A. 



do 



Aphis sp. B. 



Aphis rumicis 



Macrosiphum so- 

 lanifolii . 



Percentage of aphids dead 

 within — l 



hours. 



98 

 100 



1 

 day. 



98 

 75 

 100 

 100 

 100 

 100 



too 



95 





 



2 

 days. 



days. 



5 



10 







5 



10 



25 







5 



95 



100 



90 



99 



80 



90 



99 



100 



90 



99 



50 



95 















i Where a test did not continue for 3 days, columns are left blank. 



