PLANTS — INSECTICIDAL PROPERTIES. 
15 
Table 2. — Comparative results obtained by dusting aphids with various 
powders — Continued. 
Species and preparation. 
Esti- 
mated 
number 
of indi- 
viduals. 
Num- 
ber of 
sets. 
Percentage of aphids dead within— 
Sample 
No. 
6 hours. 
1 day. 
2 days. 
3 days 
4 days. 
103 
Aphis sp. A: 
100 
100 
100 
500 
500 
1,500 
1,000 
1,500 
100 
300 
200 
1,000 
500 
1 
1 
1 
1 
1 
3 
2 
3 
1 
1 
1 
2 
1 
95 
25 
10 
20 
20 
86 
20 
20 
99 
50 
99 
100 
20 
30 
88 
50 
43 
100 
99 
98 
100 
110 
100 
100 
80 
80 
98 
75 
70 
50 1 
521 
522 
"Cube" 
Maerosiphum sp. A: 
Do 2 
503 
Pyrethrum 
100 
85 
83 
110 
Derris 
92 
501 
"Cube" 
97 
503 
Maerosiphum sp. B: 
501 
Maerosiphum solanifolii: 
"Cube" 
100 
100 
501 
Aphis rumicis: 
"Cube" 
103 
Macrosiphonella sanborni: 
110 
100 
\'" 
No. 200 powder of bark. 
2 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-water ex- 
tracts. 
Sample 
No. 
Preparation and how 
used. 
Insects tested. 
Esti- 
mated 
number 
of indi- 
viduals. 
Num- 
ber of 
sets. 
Species. 
Percentage of aphids dead 
within— 1 
6 
hours. 
1 
day 
2 
days. 
3 
days. 
56 
502 
103 
110 
501 
113 
103 
110 
56a 
301a 
35fa 
502a 
103a 
1 
501a 
103a 
1 
501a 
103b 
103b 
110b 
110b 
501b 
501b 
501c 
501c 
Fumigant: 
Sabadilla burned . 
Hellebore burned 
Pyrethrum burned 
Derris burned 
"Cube" burned... 
Sabadilla burned. . 
Pyrethrum burned 
Derris burned 
Decoction not filtered : 
Sabadilla sprayed . 
C h i n a b e r r y 
sprayed. 
Amianthium 
sprayed 
Hellebore sprayed. 
Pyrethrum 
sprayed. 
Derris sprayed 
"Cube" sprayed. . 
Pyrethrum 
sprayed. 
Derris sprayed 
"Cube" sprayed. . 
Water extract (decoc- 
tion filtered): 
Pyrethrum 
spraved. 
Do 
Derris sprayed 
Do 
"Cube" spraved. 
Do 
Infusion not filtered: 
"Cube" spraved.. 
Do 
L00 
100 
100 
J 00 
100 
100 
100 
1011 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
200 
600 
Maerosiphum sp . C . 
do 
Aphis rumicis. 
Maerosiphum 
lanifolii. 
95 
do 
100 
do 
do 
Myzus persicae 
do 
98 
100 
do 
Aphis sp. B 

do 

do 

do 

do 
50 
do 
do 


Aphis sp. A 
do 
50 

...do 

do 
Aphis sp. B 


do 
Aphis sp. A 
5 
5 
do 
Aphis sp. B 
10 
5 
75 
100 
loo 
100 
100 
100 
90 
5 
10 

5 
10 
25 

5 
95 
100 
90 
99 
SO 
90 
99 
100 
90 
99 
50 
95 
i Where a test did not continue for 3 da vs. columns are left blank. 
