REMEDIAL MEASURES. 
65 
additional object of this experiment was to observe the readiness with 
which beetles that had just emerged from the soil and had not had a 
previous opportunity of feeding on unsprayed foliage would feed on 
poisoned foliage as compared with beetles which were taken from 
vineyards and which had fed to some extent upon unsprayed vines. 
Accordingly 30 beetles, on emerging July 8, from soil inclosed with 
wire screens, were placed on a sprayed plant in pot I. Thirty more 
beetles collected in a vineyard, June 30, and fed on unsprayed leaves 
until July 8, were placed (July 8) in pot II, also containing a sprayed 
plant. At the same date 15 beetles which had just emerged were 
placed on an unsprayed plant in pot III. 
Table XXIV shows the death rate of the beetles in these three 
cages. 
Table XXIV. — Experiments v:ith -poison sprays against grape root-worm beetles feeding 
on vines in confinement at North East, Pa., in 1909. 
Pot I. 
Pot II. 
Pot III. 
30 beetles emerged 
from soil July 8, 
and at once re- 
moved to 
sprayed vine. 
30 beetles taken on 
vines in the field 
June 30 and 
placed on 
spraved vine 
July 8. 
15 beetles emerged 
from soil July 8, 
and removed at 
once to un- 
sprayed vine. 
Number 
of dead 
beetles. 
Date. 
Number 
of dead 
beetles. 
Date. 
Number 
of dead 
beetles. 
Date. 
16 
12 
2 
Julv 9 
July 10 
July 11 
3 
10 
13 
2 
1 
1 
Julv 9 
July 10 
Julv 11 
Julv 12 
July 13 
July 17 
1 
1 
1 
1 
3 
1 
Julv 15 
July 27 
Julv 29 
Julv 31 
Aug. 14 
Aug. 15 
Aug. 28 
30 
30 
15 
Total. 
It was observed that the beetles just emerged from the soil and 
which had been placed in pot I without having had an opportunity 
to come in contact with unsprayed foliage fed as readily and indis- 
criminately on the poisoned leaves as did those placed on the unsprayed 
plant in pot III. The beetles placed on the other sprayed plant in 
pot II, which had had 8 or 10 days of feeding on unsprayed leaves, 
fed less upon the sprayed foliage, especially for the first 24 hours. A 
glance at the table will show that 50 per cent of the beetles in pot J 
died in 24 hours as against 10 per cent in pot II. On the fourth day 
all beetles in pot I had died and also 85 per cent of those in pot II, 
whereas it was not until the eighth day of the experiment that the 
first dead beetle was found in pot 111, and 73 per cent of the beetles 
remained alive on this plant for more than a month. 
51282°— Bull. 89—10 5 
