178 THE PLUM CURCULIO. 
Table LXXXIX. — Effect of stirring soil on destruction of pupae of the plum curculio. 
Locality and date. 
Lot 
No. 
Num- 
ber of 
larvae 
used. 
Treatment given soil. 
Adults 
emerg- 
ing. 
Per- 
centage 
of 
adults 
from 
larvaa. 
Aver- 
age 
per- 
centage 
adults 
from 
treated 
boxes. 
Aver- 
age 
per- 
centage 
adults 
from 
un- 
treated 
boxes. 
Per- 
centage 
gain 
from 
treat- 
ment. 
1906. 
North East, Pa 
1 
2 
3 
4 
1 
2 
1 
200 
200 
200 
200 
451 
451 
558 
51 
468 
137 
98 
173 
191 
173 
191 
Soil disturbed July 11 
and 20. 
do 
25 
32 
71 
75 
60 
135 
20 
24 
267 
59 
2 
17 
21 
12 
119 
98 
12.50 
16.00- 
35.50 
37.50 
13.30 
29.93 
3.58 
47.06 
57.05 
43.07 
2.04 
17.35 
12.14 
6.28 
68.79 
51.31 
Do 
14.25 
Do 
Soil not disturbed 
do 
Soil disturbed June 23.. . 
Soil not disturbed 
Soil disturbed July 8 
and 15. 
Soil disturbed July 15. .. 
Soil not disturbed 
do 
Soil disturbed f r e - 
quently. 
Soil not disturbed 
Soil disturbed June 17... 
Soil disturbed June 8 
Soil not disturbed 
..do 
Do 
13.30 
36.50 
22.25 
1908. 
Siloam Springs, Ark 
Do 
29.93 
16.63 
Washington, D, C 
Do 2 
7.22 

Do 3 
Do. . 
4 
1 
2 
1 
2 
3 
4 
2.04 
53 88 4fi fifi 
1910. 
Do , 
17.35 
15 31 
Barnesville, Ga 
Do 
9.06 
Do... 
Do. . 
59.61 
50.55 
10.20 
43.85 
33.65 
As will be noted, there is with one exception an important decrease 
in the number of adult curculios emerging from boxes in which the 
earth was stirred. In the case of lot No. 2, at Washington, D. C, 
an unusually large number of adults emerged. The larvae were 
placed in this box June 29 and were doubtless all in the pupal stage 
by July 15, when the cultivation was given. It is to be noted, how- 
ever, that there is a considerable variation in the percentage of insects 
killed by stirring the soil from the different localities. This perhaps 
results from differences in the methods of treatment. The total 
average percentage of adults emerging from the treated boxes, 
namely, 10.20, as compared with the total average from all untreated 
boxes, namely, 43.85, shows a difference in favor of stirring the soil 
of 33.65 per cent. Comparing the total number of beetles emerging 
from the untreated boxes, 841, with the total number of beetles 
from the treated, 196, shows a probable number killed by treatment 
of 645, a percentage of benefit of 76.75. 
SPRAYING WITH ARSENICALS. 
It is impossible to state with certainty who first used arsenical 
poisons for the control of the plum curculio. They doubtless came 
in along with the use of Paris green against cankerworms and the 
codling moth. Paris green was recommended by Mr. G. M. Smith, 
