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 
larve diminished aiso 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 larvee; 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 tie yellow-bear caterpillar (Diacrisiavirginica) 
on sugar beets and celery. 
Experi- 
ment | Date. Insecticide used. Larve killed. Remarks. 
num- | | 
ber. | 
| 1909 | | 
11 ee 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. 
Os SU are eee. donee. | Arsenate of lead 8 pounds to |..... GOR s25ebs | Applied to sugar beets with 8-row 
100 gallons of water. | sprayer. 
Seay Le | Sept. 9 | Arsenate of lead 10 pounds |..... Gon sas a2 eee | Do. 
| | to 100 gallons of water. | | 
Arg a Sept. 7-8 | Arsenate of lead 16 pounds |..-.. GOee rate sly 8 to 100 mixture applied twice to 
| to 100 gallons of water. | same plat of sugar beets with 
| F |  8-row sprayer. 
eee | Sept. 21) Arsenate of lead 8 pounds to |... .- Gomes gece ees ' Applied with hand sprayer to 
| | _ 100 gallons of water. |) ‘celery. 
(eee | 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 larvee deserted 
lons of water. | this plat because it was also 
| sprayed with lye-sulphur solu- 
| tion for the common red 
| | spider. 
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. 
Sitios ey | 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. 
Qe oie Sept. 21) Paris green 10 pounds and |..... Ge eisacctaes 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. 
LOw sos 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. 
