THE COLORADO POTATO BEETLE IN VIRGINIA. 5 
Examination the following day showed no living larve present on 
the vines. A small number of dead larve 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 larve in twenty-four hours, and all of the larve in forty- 
eight hours. No injury as a result of the poison was seen at this time 
or later. . 
Expervment 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 larve had reached 80 
to 85 per cent. The remainder of the larve 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 larve were by this 
time thoroughly exterminated on the plat. 
Expervment 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 larve 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 suff- 
cient to thoroughly destroy the larve by forty-eight hours afterwards. 
This mixture killed 90 per cent of the larve 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 larve had been destroyed. 
Extermination was complete, with no injury to the foliage. This 
mixture seems superior to the plaster mixture used in experiment 
