The " Normal " formula is: cop per sulphate, 6 pounds; quicklime, 4 pounds; water, 45 gallons. More re cent experiments appear to favor a still more dilute solution.
We recommend for a strong solu tion: copper sulphate, 4 pounds; quicklime, 4 pounds; water, 50 gal lons.
For is weaker solution we recom mend: copper sulphate, 2 pounds; quicklime, 2 pounds; water, 50 gal lons.
In compounding this mixture, first put the copper sulphate on a piece of cheese cloth, tying the ends to gether so it will not spill, and sus pend it from a stick in a bucket of water. Fill the barrel or tank to contain the solution half full of wa ter, carefully measuring the amount used. When the copper sulphate is fully dissolved, pour it into the re ceptacle. Thoroughly slake the lime and strain the milk of lime into the barrel. Then add sufficient water to make 50 gallons.
Stock Solution. — Weighing the copper and lime at the time of mak ing the mixture is sometimes incon venient, but as the mixture deterio rates if allowed to stand, it is not feasible to make it up in advance. It is, however, a good idea to make up stock preparations of sulphate of copper and of lime, and have them ready for mixing when required. The lime should be fresh quicklime and when slaked must be covered with water to keep out the air. Thus a stock mixture can be kept all sum mer without harm.
To prepare a stock solution of sulphate of copper, suspend some evening 50 pounds of copper sul phate in 25 gallons of water. The next morning, if the water is well stirred, each gallon of water will contain 2 pounds of sulphate. This will form the stock solution of cop per sulphate. The undissolved sul phate must, of course, be removed.
Put in the spray barrel 2 gallons of this solution, which is equivalent to 4 pounds of copper sulphate. Fill the spray barrel half full of water before adding the lime. This is nec essary, because if lime is added to a strong solution of sulphate of cop per, the mixture will curdle. Now stir up the water in the lime barrel so as to make a dilute milk of lime, but do not let it get as thick as cream, otherwise lumps will form and clog the spray nozzle. To de
termine the amount of milk of lime necessary (which will depend upon the strength you desire), get from a drug, store a vial of ferrocyanide of potassium (yellow prussiate of pot ash). Continue to add lime to the mixture as long as drops of the cyanide continue to change from a yellow to a brown color. When the change of color ceases, add another pail of milk of lime to make the nec essary amount a sure thing. A little too much lime does not do any harm. The barrel can now be filled with water, and the Bordeaux mixture is ready for use.
This is the most generally useful treatment for fungous diseases.
The strong solution (third recipe) may be used on most plants, but for cherry trees, peach trees, and water melon vines, the weaker solution (fourth recipe) is to be preferred.
Kerosene Emulsion.—Experiments seem to indicate that all soft-bodied sucking insects are destroyed by con tact with kerosene. Pure kerosene may be applied to the hardier trees in winter when they are not grow ing. For application to growing trees and foliage in summer, a mix ture called kerosene emulsion is rec ommended, as follows: hard, soft, or whale-oil soap, pound; boiling soft water, 1 gallon; kerosene, 2 gal lons.
The soap is first dissolved in the boiling water, then the kerosene is added and churned by the pump from five to ten minutes. Before using, this must be reduced with wa ter from one fourth to one tenth its strength. A strong emulsion must be used for scale insects, as the San Jose scale.
For plant lice, thrips, red spiders, and mealy bugs, weaker solutions may be used. Soft-bodied insects and cabbage worms, currant worms, etc., can be destroyed by these. The emulsion should be made shortly be fore using.
Formula for San Jose Scale.—A special formula for San Jose scale is as follows: whale-oil soap, 1 pound; boiling soft water, 1 gallon; kerosene, 2 gallons. Mix, churn, and reduce with 6 times as much water as emul sion. Use this in summer to kill the young and tender scales.