CALIFORNIA CITRUS CULTURE. 65 
SPRAYS. 
For many years spraying was the only known method for the control 
of citrus pests, but the discovery of fumigation and the use of hydro- 
cyanic gases has practically eliminated commercial spraying in the 
citrus orchards for injurious insects. Fungus diseases, however, are 
still to be controlled by spraying, including such fungicides as Bordeaux 
mixture and lime-sulphur. 
Plant lice are controlled entirely by the use of contact sprays, chief 
of which are carbolic acid emulsion and tobacco decoction. 
In a number of instances it has been found practical to control certain 
scale insects by the use of sprays. Young seed bed stock is usually 
dipped in resin wash or sprayed with an oil emulsion to kill young 
scale. It has been found that the carbolic acid emulsion is a cheap and 
ready means of controlling the citrus mealy bug. 
Only the most important spray formule are given in this work: 
Bordeaux Mixture. 
UWnslaked: lim 6s. se a ee 4 pounds 
Copper sulphate (bluestone) _-______________-_-__--__________ 4 pounds 
Wraten ate a ee eh Se ee Pe ee 50 gallons 
The task of mixing these chemicals, where large quantities of the 
spray is used, is no small thing in itself. A great deal of study has 
been given to the construction of suitable mixing apparatus. 
The first consideration is to get the materials high enough on a plat- 
form so that they can-be easily and rapidly placed in the spraying 
tanks of the power machines. This is done by constructing at convenient 
places in the orchard, platforms large enough to hold a large box for 
slaking lime, a lime solution agitator, and a vat for dissolving bluestone. 
Such a platform is about 12 feet square and 44 feet high. A large 
standpipe for filling the tanks is desirable, or the water must be pumped 
into the tank while the solutions are being added. 
The lime is first slaked in a common vat for that purpose. It is 
necessary to keep the slaked hme agitated properly when it is being 
-drawn off to mix with the bluestone in the spraying tank. 
The bluestone vat contains slats, across the entire box or simply 
across one end. These slats must be low enough so that the bluestone, 
which is placed upon them in sacks, will be completely immersed in the 
water. This method admits quick dissolving of the bluestone, much 
more rapidly than if simply poured into the tank and stirred. 
The lime and bluestone are mixed with a given amount of water so 
that the proper quantities of the resultant solutions can be measured 
.so as to give the mixture the strength of the above formula. 
5—cc 
