THE COLOEADO POTATO BEETLE IN VIRGINIA. 5 
Examination the following day showed no living larvae present on 
the vines. A small number of dead larvae still clung to the stems in 
some places. No injury to the foliage was seen nor did any afterwards 
appear. 
Experiment No. 3. — Arsenate of lead was applied at the rate of 6 
pounds to 50 gallons of water. The day was bright, with a tempera- 
ture of 87° F. and a southwest breeze. 
An application of this strength resulted in destroying 85 to 90 per 
cent of the larvae in twenty-four hours, and all of the larvae in forty- 
eight hours. No injury as a result of the poison was seen at this time 
or later. 
Experiment No. 4- — For this plat, Paris green without lime was used 
at the rate of 4 pounds to 50 gallons of water. The weather was as 
in Experiment No. 3. 
Twenty-four hours later the mortality of the larvae had reached 80 
to 85 per cent. The remainder of the larvae were in a dying condition 
and no damage to the vines was noted at this time as a result of the 
arsenic. By the next day, however, some traces of burning were to 
be seen although not of a serious nature. The larvae were by this 
time thoroughly exterminated on the plat. 
Experiment No. 5. — This plat was sprayed with a Paris-green mix- 
ture, consisting of 3 pounds of Paris green with Bordeaux mixture, 
composed of 4 pounds copper sulphate, 6 pounds of lime, and 50 gal- 
lons of water. The day was bright, with a temperature of 85° F. The 
mixture was applied thoroughly and remained on the leaves well. 
An examination of the plants forty-eight hours after treatment 
showed no injury to the leaves of the potatoes, while the larvae had 
succumbed to the poison, the vines being completely cleared. 
Experiment No. 6. — This plat was treated with a mixture of Paris 
green and land plaster at the rate of 1 pound of Paris green to 50 
pounds of plaster, the mixture being put in a coarse burlap bag and 
sifted over the plants by a negro laborer in the usual plantation 
manner, the amount of dust used being at the rate of 320 pounds per 
acre. The wind prevailing at the time carried a large part of the dust 
from the plat as it was applied, but the portion remaining was suffi- 
cient to thoroughly destroy the larvae by forty-eight hours afterwards. 
This mixture killed 90 per cent of the larvae during the first twenty- 
four hours, and is very effective in controlling the potato beetle. 
Experiment No. 7 . — To this plat Paris green powder was applied, 
mixed with lime at the rate of 1 pound Paris green to 10 pounds 
sifted air-slaked lime. The mixture was applied with a powder 
bellows early in the morning and the application was at the rate of 30 
pounds per acre. 
Twenty-four hours later all of the larvae had been destroyed. 
Extermination was complete, with no injury to the foliage. This 
mixture seems superior to the plaster mixture used in experiment 
