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 larve 
were killed, but as the amount of poison diminished the number of dead 
larvee 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 larve 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 larve; 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 Date. Insecticide used. Larve killed. Remarks. 
nuim- | 
ber. 
1909. 
Lae Baas Sept. 7 | Arsenate of lead 6 pounds to | Very few........-. Applied to sugar beets with bar- 
100 gallons of water. rel sprayer fitted with 8-row 
| attachment. 
eee B75 GIOiScee | Arsenate of lead 8 pounds to |.._.- ClO eiseabeee ee | A pplied to sugar beets with 8-row 
| 100 gallons of water. | sprayer. 
Sie 8 Cea | Sept. 9 Arsenate of lead 10 pounds |..... Coss eth -2jac22 | Do. 
| | to 100 gallons of water. | 
Ae Sept. 7-8 Arsenate of lead 16 pounds |....-. Gee cee seeeces | 8 to 100 mixture applied twice to 
| to 100 gallons of water. | same plat of sugar beets with 
|  §-row sprayer. 
Bs ee Sept. 21, Arsenate of lead 8 pounds to |..-.. dOsrss22450--e | Applied with hand sprayer to 
| 100 gallons of water. celery. 
65 x8s5 2s Sept. 25 Paris green 5 pounds and | At least 15 per | Applied to celery with hand 
lime 5 pounds to 100 gal- cent. sprayer. The larve deserted 
| lons of water. | this plat because it was also 
: ; sprayed with lye-sulphur solu- 
tion for the common red 
| _ spider. 
Ff eae Sept. 1 | Paris green 8 pounds and | Very few.........- | Applied with 8-row sprayer to 
| lime 8 pounds to 100 gal- | sugar beets. 
| lons of water. 
Sess | Sept. 12 Paris green 10 pounds and | Practically 100 per | Applied with hand sprayer to 
lime 10 pounds to 100 gal- cent. celery. 
lons of water. 
OP 2453 | Sept. 21) Paris green 10 pounds and |..... Ovens ste Applied with hand sprayer to 
| lime 10 pounds to 100 gal- celery. Repetition of experi- 
lons of water. ment No. 8 to determine effect 
| , | on older larvee. 
OES oe Sept. 14 Paris green 10 pounds and | Varying number..| Applied to sugar beets. Results 
lime 10 pounds to 100 gal- inconclusive because of poor 
lons of water. application with faulty 
sprayer. 
