Apr. 26, 1924 
Fumigation of Bean Weevils 
351 
Table IV.— Effect of different kinds of fumigation for varying lengths of time on 
eggs of Bruchus quadrimaculatus 
Num- 
Dos¬ 
age 
Ex¬ 
pos¬ 
ure 
Num¬ 
ber 
hatched 
Num¬ 
ber 
failed 
to 
Temperature 
Humidity 
ber 
of 
Date de¬ 
posited 
Date 
treated 
Material used 
per 
1,000 
cubic 
feet 
Maxi- 
Mini- 
Maxi- 
Mini- 
hatch 
mum 
mum 
mum 
mum 
Lbs. 
Ilrs. 
0 F. 
°F. 
°F. 
°F 
60.... 
May 16 
May 17 
Liq. HCN—_ 
1.8 
24 
0 
50 
70 
62 
70 
45 
60.... 
-..do_ 
...do. 
_do. 
1.8 
24 
0 
50 
70 
62 
70 
45 
60_ 
...do_ 
( a ) 
May 17 
(°) 
June 8 
42 
8 
85 
51 
92 
44 
39.... 
...do_ 
_do_ 
1.8 
24 
1 
38 
70 
62 
70 
45 
38_ 
___do_ 
28 
10 
85 
51 
92 
44 
50.... 
June 7 
CS 2 _ 
6 
21 
0 
9 
50 
68 
64 
70 
66 
50_ 
—do. 
...do. 
.do. 
6 
21 
50 
68 
64 
70 
66 
50.... 
...do. 
(“) 
(°) 
43 
7 
87 
50 
83 
50 
60.... 
—do_ 
49 
1 
87 
50 
83 
50 
50.... 
June 10 
June 11 
Liq. HCN.... 
3.5 
48 
0 
50 
75 
62 
80 
58 
50.... 
—do. 
...do. 
_do_ 
3.5 
48 
0 
50 
75 
62 
80 
58 
50_ 
—do. 
...do. 
.do.. 
3.5 
48 
0 
50 
75 
62 
80 
58 
50.... 
___do_ 
_do_ 
.do. 
3.5 
48 
0 
50 
75 
62 
‘80 
58 
50.... 
...do. 
(“) 
( a ) 
47 
3 
83 
64 
82 
54 
50_ 
___do_ 
49 
1 
83 
64 
82 
54 
50.... 
...do. 
(*) 
Aug. 16 
43 
7 
83 
64 
82 
54 
50.... 
Aug. 15 
Liq. HCN.... 
2 
48 
0 
50 
92 
64 
79 
46 
50_ 
—do_ 
...do. 
.do.. 
2 
48 
0 
50 
92 
64 
79 
46 
50.... 
...do. 
( a ) 
(*) 
Aug. 17 
44 
6 
92 
64 
79 
46 
50_ 
—do. 
36 
14 
92 
64 
79 
46 
50.... 
—do. 
CS 2 and 29 
31 
1 
0 
50 
82 
82 
inch-vacuum. 
60.... 
_do_ 
...do. 
_do . .. 
31 
1 
0 
50 
82 
82 
50_ 
___do. 
(°) 
(“) 
Aug. 18 
44 
6 
92 
64 
79 
46 
60.... 
...do. 
36 
14 
92 
64 
79 
46 
50.... 
Aug. 17 
Liq. HCN_ 
1.3 
90 
0 
50 
91 
58 
79 
43 
50.... 
...do. 
_._do. 
_do.___. 
1.3 
90 
0 
50 
91 
58 
79 
43 
50_ 
___do_ 
(*) 
(°) 
Aug. 23 
&37 | 
b 35 
13 
91 
58 
79 
43 
50.... 
_do. 
15 
91 
58 
79 
43 
50.... 
Aug. 22 
HCN, pot 
method. 
*3.4 
48 
0 
50 
82 
69 
71 
51 
50.... 
—do_ 
...do. 
.do. 
*3.4 
48 
01 
50 
82 
69 
71 
51 
60.... 
...do. 
(“) 
(<*) 
Aug. 25 
*> 37 | 
13 
82 
69 
71 
51 
50.... 
...do_ 
& 35 | 
15 
82 
69 
71 
51 
50.... 
Aug. 24 
HCN, pot 
method. 
* 1.8 
90 
0 i 
f 
i 
50 
84 
67 
66 
51 
50_ 
—do_ 
—do. 
.do.—. 
*1.8 
90 
0 1 
50 
84 
67 
66 
51 
60.... 
...do. 
<*) 
C) 
34 | 
d 11 
84 
67 
66 
51 
50.... 
—do_ 
28 | 
d 22 
84 
67 
66 
51 
° Control. 
h Figures seem to indicate that the controls were identical on August 17 and August 22, which is not the 
case. 
« Dosage of sodium cyanide employed to generate the gas. 
d Mites, Pediculoides ventricosus Newp., probably account for the low hatch and in one of the experiment 
the five eggs unaccounted for. 
EFFECT OF FUMIGATION UPON FORMS WITHIN THE SEEDS 
The data in Table V indicate that 2 pounds of carbon disulphide per 1,000 
cubic feet at 53° to 61° F. for 24 hours was not effective in killing the unemerged 
adults, pupae, full-grown larvae, or half-grown larvae, of Bruchus ohtectus f but was 
effective in killing the young larvae. The same dosage gave a complete kill when 
adults free of seeds were treated. (See Table I.) Three pounds of carbon disul¬ 
phide at 53° to 58° F. for 24 hours made a complete kill, as did 1J pounds for 
48 hours at 60° to 68° F. One and eight-tenths pounds of liquefied hydrocyanic 
acid per 1,000 cubic feet at 62° to 70° F. for 24 hotirs did not kill all the un¬ 
emerged adults and pupae, but it killed the larvae. The same dosage killed all 
eggs of B. ohtectus and emerged adults of both species of weevils. (See Tables 
I to IV.) 
