THE BROAD-BEAN/ WEEVIL. 
75 
Experiment No. 5 — Fifteen pounds of infested beans were dipped in 20 gallons of 
water which had been heated to the boiling point in an iron caldron. The water had 
just ceased boiling and the beans were allowed to remain in the water 5 minutes. 
Experiment No. 6. — A second lot was dipped for 1 minute. The effect upon the 
beetles and upon the germinating power of the beans may be expressed in tabular 
form, as follows: 
Table III. — Hot-water treatment against broad-bean weevil and its effects on germi- 
nating power of treated beans. 
Tempera- 
ture. 
Time of 
immersion. 
Number 
beans 
counted. 
Percentage 
of beetles 
killed. 
Percentage 
of germi- 
nation- 
"F. 
'210 
210 
Minutes. 
5 
1 
98 
111 
100 
100 
2.0 
38.7 
From the preceding data it is evident that on a large scale, at least, the germinating 
power of the beans is seriously injured. The germination was not injured by the small- 
scale treatments of a similar nature. 
Experiment No. 7. — In another test the infested beans were placed in cold water in 
the iron caldron and the temperature gradually raised. The first beans were removed 
when the temperature reached 140° F. and the last at 170° F. The results of these 
experiments follow: 
Table IV. — Hot-water treatment against broad-bean weevil and its effects on germi- 
nating power of treated beans. 
Tempera- 
ture. 
Time of 
immersion. 
Number 
beans 
counted. 
Percentage 
of beetles 
killed. 
Percentage 
of germi- 
nation. 
°F. 
Minutes. 
Per cent. 
130 
23 
76 
94 
86.0 
140 
27 
130 
100 
98.4 
150 
32 
129 
100 
88.3 
160 
39 
91 
100 
82.4 
170 
43 
116 
100 
56.8 
It is evident from the foregoing data that 140° F. is the lowest temperature at which 
all of the insects are sure to be killed and that the germinating power of the bean is not 
seriously injured until the temperature reaches 160° F. or over. 
When removed from the water the beans were somewhat soaked, but were in good 
shape for planting. 
METHODS OF CONTROL. 
Possibility of eradication. — The broad-bean weevil is by no means a 
difficult species to control and if proper action could be enforced there 
is every probability that the insect could be stamped out in its lim- 
ited occurrence in this country. This would, however, in all proba- 
bility require special legislation. By the abandonment, in the 
infested district, of the culture of broad beans, and possibly other 
beans and other large legumes which might furnish the insect with 
food, this result could be accomplished, if at the same time soaking 
and fumigation of seed, " holding over," and other remedies were 
