NOTES ON THE YELLOW-BEAR CATERPILLAR. 
65 
type. The hose could not be handled to advantage, and an extremely 
poor and unsatisfactory application was made. 
Where the coat of poison was thick, a good many of the larvae 
were killed, but as the amount of poison diminished the number of dead 
larvae diminished also and the experiment was considered a failure 
from every standpoint. 
Shortly before any of the above experiments were undertaken, one 
of the beet growers made tests with Paris green at the rates of 1 
pound and 2 pounds in 50 gallons of water against these larvae on 
sugar beets. These tests were not made under the writer's direction, 
but from all appearances careful work was done. The poison did 
not kill a material number of the larvae; and as these strengths 
were so obviously ineffective, the apparently excessive strengths 
were used in the experiments which were conducted later. 
In none of the experiments with arsenate of lead was the foliage, 
either of sugar beets or celery, burned, but with Paris green, wherever 
the foliage was partly eaten there was some burning. This, however, 
was not serious in any case. Leaves remaining entire, even the very 
tender ones at the center of the plants, were uninjured. 
The weather conditions were ideal during the time these experi- 
ments were made. 
The results of these spraying experiments are summarized in the 
following table: 
Results of experiments with sprays against the yellow-bear caterpillar {Diacrisia virginica) 
on sugar beets and celery. 
Experi- 
ment 
num- 
ber. 
1 
Date. 
Insecticide used. 
Larvae killed. 
Remarks. 
1 
1909. 
Sept. 7 
do . 
Arsenate of lead 6 pounds to 
100 gallons of water. 
Arsenate of lead 8 pounds to 
100 gallons of water. 
Arsenate of lead 10 pounds 
to 100 gallons of water. 
Arsenate of lead 16 pounds 
to 100 gallons of water. 
Arsenate of lead 8 pounds to 
100 gallons of water. 
Paris green 5 pounds and 
lime 5 pounds to 100 gal- 
lons of water. 
Paris green 8 pounds and 
lime 8 pounds to 100 gal- 
lons of water. 
Paris green 10 pounds and 
lime 10 pounds to 100 gal- 
lons of water. 
Paris green 10 pounds and 
lime 10 pounds to 100 gal- 
lons of water. 
Paris green 10 pounds and 
lime 10 pounds to 100 gal- 
lons of water. 
Applied to sugar beets with bar- 
rel sprayer fitted with 8-row 
attachment. 
Applied to sugar beets with 8-row 
sprayer. 
Do. 
2 
do 
3 
Sept. 9 
Sept. 7-8 
Sept. 21 
Sept, 25 
Sept, 1 
Sept. 12 
Sept. 21 
Sept. 14 
do 
4. 
do 
8 to 100 mixture applied twice to 
same plat of sugar beets with 
8-row sprayer. 
Applied with hand sprayer to 
celery. 
Applied to celery with hand 
sprayer. The larvae deserted 
this plat because it was also 
sprayed with lye-sulphur solu- 
tion for the common red 
spider. 
Applied with 8-row sprayer to 
sugar beets. 
Applied with hand sprayer to 
celery. 
Applied with hand sprayer to 
celery. Repetition of experi- 
ment No. 8 to determine effect 
on older larvae. 
Applied to sugar beets. Results 
inconclusive because of poor 
application with faulty 
sprayer. 
5 
do 
6 
7 
At least 15 per 
cent. 
8 
9 
Practically 100 per 
cent. 
do 
10 
Varying number.. 
