February, ’23] 
CORY: DUSTING FOR PEA APHIS 
83 
The principal tests were on the percentage of nicotine most effective, 
the quantity that should be used and the method of application. 
Table IV shows in condensed form the results. While the dust from 
several manufacturers was used, no attempt is made to show a compari¬ 
son as the conditions were different in each case. 
The percentage of kill is based on counts of infested plants prior to 
dusting, and similar counts twelve hours after dusting. 
Table IV. Tests of Nicotine Dust 
Byrn Farn, Cambridge, Md. 
Field A. 
Exp 
Date 
Kind of dust 
Quantity 
in lbs. 
per acre 
Per cent 
kill 
Remarks 
4 acres 
1 
9/22/22 
Niagara, 2% 
15 
44 
No canvas. 
2 
»» 
Niagara, 2% 
30 
71 
No canvas. 
3 
»» 
Niagara, 3% 
30 
68 
10 ft. canvas. 
4 
11 
Niagara, 5% 
30 
78 
10 ft. canvas. 
5 
10/7/22 
Niagara, 3% 
25 
75-80 
3 lbs. Arsenate of 
lead to kill loopers. 
Slight breeze. Temperature 70°-66. Noon to 4:30. 2 rows allowed for drift. 
Field B. 
2 acres 
9 
1 
9/23/22 
Niagara, 5% 
25 
63 
10 ft. canvas. 
2 
< 4 
Niagara, 3% 
43 
71.4 
10 ft. canvas. 
Temperature 78°. No breeze. Noon. 
Field C. 
1 y/ acres 
1 
9/23/22 
i i 
Niagara, 5% 
50 
85- 
-100 
18 ft. canvas. 
2 
Niagara, 5% 
25 
85- 
-100 
18 ft. canvas. 
Temperature 78°. No breeze. Noon. Higher per cent kill on middle rows. 4 rows between plots. 
Average infestation 16.7%. 
Austin Farm, Cambridge, Md. 
Exp 
No. 
Date 
Kind of Dust 
Quantity 
in lbs. 
per acre 
Per cent 
kill 
Remarks 
1 . 
9/26/22 
Dosch, 2.4% 
no 
85-95 
With the wind. 
2. 
( « 
n a 
60 
65 
Against the wind. 
3. 
i < 
< < ti 
30 
50 
Dusted with and against the wind. 
4. 
4 i 
a <« 
30 
50 
With the wind. 
5. 
< 4 
Check 
T< 
smperature 
75°-80°. High wi 
nd. Noon. 
3 er cent plants infested September 21, 1922—41.5 
The tests herein recorded were supported by demonstration dusting 
on a commercial scale at eight farms. The results on these farms, to¬ 
gether with the above data, indicates to us that less than thirty pounds 
per acre of nicotine dust is not practicable and that a high nicotine 
content is preferable to the low content. 
The use of a trailer of canvas is highly desirable in order to get tne 
maximum fumigation, and the dusting should be done in as calm weather 
as possible. Good results seem to be possible at temperatures around 
70° F. 
