Insect and Fungous Enemies of the Grape. 65 
INSECTICIDES. 
ARSENATE OF LEAD. 
Arsenate of lead is the arsenical principally used in spraying 
grapes, and the commercial article is probably universally employed. 
It comes on the market in both powdered and paste forms, though 
the former is now rapidly replacing the latter. Arsenate of lead is 
used for the control of biting or chewing insects, such as the grape- 
berry moth, the grape rootworm, the rose-chafer, various caterpillars, 
and the like. It can be added to Bordeaux mixture, used for the 
control of fungous diseases, without reducing its effectiveness, or 
used alone in water, in which case there should be added to the spray 
the milk of lime from slaking 2 or 3 pounds of good stone lime 
for each 50 gallons to obviate danger of burning the foliage. 
The powdered arsenate of lead is used on grapes mostly at the 
rate of 14 pounds, and the paste form at the rate of 3 pounds per 
50 gallons of spray. Before adding the powdered arsenate of lead 
to the spray tank it should be mixed with a little water. Water 
should also be added to the paste and the whole worked until of a 
thin consistency. 
NICOTINE SOLUTION. 
Nicotine or tobacco extract is used principally for the control of 
the grape leafhopper and plant-lice. It may be extracted from 
tobacco refuse by soaking in the full quantity of water, with occa- 
sional stirring, for a period of about 24 hours. This removes about 
70 or 80 per cent of the nicotine; and after straining to remove coarse 
particles the solution is ready for use. The nicotine content of 
tobacco refuse, stems, etc., varies widely, and the number of pounds 
to use with a given quantity of water to obtain an effective extract 
can not be accurately indicated without chemical analysis. In gen- 
eral, however, a pound of the refuse for each gallon of water will 
yield sufficient nicotine for a killing spray. Those especially in- 
terested in the utilization of refuse tobacco for spraying purposes 
should consult Farmers’ Bulletin 908, United States Department of 
Agriculture. 
Nicotine is offered for sale in various grades, and a concentrated 
preparation is the so-called 40 per cent nicotine sulphate, containing 
40 per cent of nicotine. The nicotine strength of the commercial 
articles will not affect their insecticidal value if diluted so that the 
spray will contain about 0.05 per cent of nicotine. In spraying with 
homemade tobacco extract or with commercial nicotine solution in 
water a soap should be added, preferably rosin fish-oil soap, at the 
rate of 1 pound to 50 gallons of spray. If this soap is not available, 
2 pounds of ordinary laundry soap may be used. 
