SPRAYING FOR CITRUS INSECTS AND MITES IN FLORIDA. 21 



sible to make emulsions by using any of the soap powders, even if 

 flour is used as a stabilizer. 



Before any spray material is applied to a tree it should be tested 

 to determine if it is a perfect emulsion. To do this, add a small 

 amount to some soft water; if no oil floats or no thick, greasy scum 

 forms, it is satisfactory. If free oil appears the emulsion is imperfect 

 and should not be used. Great care should be used to stir the con- 

 tents of the barrel thoroughly before any test is made. 



The present price of potash-fishoil soap makes the "cold-stirred" 

 formula somewhat expensive, but when the market becomes normal 

 its cost will be reasonable. It has an advantage in that it will keep 

 indefinitely and will not separate under ordinary conditions of tem- 

 perature or usage. It has an added advantage in that no apparatus, 

 other than an ordinary pail and paddle, is required for making it on 

 a small scale. 



Just at present the boiled-emulsion formula is the one which will 

 appeal to the average citrus grower in Florida. It is, beyond all 

 question, the cheapest effective insecticide for white flies and scale 

 insects. 



The oils used in the making of these formulas usually test from 

 24 to 32 Baume and have a viscosity not less than 200. The best 

 oils for spraying purposes have a viscosity of about 300 to 400 and 

 they may be purchased from any of the oil companies operating in 

 the citrus-growing belt. Petroleum fuel oil and distillate or gas oil 

 may also be used and when applied should be used at twice the 

 strength indicated for the lubricating oils. The soaps may be pur- 

 chased from any grocery or fertilizer company. 



PROPRIETARY MISCTBLE OILS. 



There are several proprietary miscible oils on the market which the 

 writer has found to give highly satisfactory results. These should 

 be diluted so that the spray material will contain somewhere between 

 f per cent and 1 per cent of oil. The writer would advise the use of 

 oil emulsions when diluted to about 1 per cent, Experience indicates 

 that such substances as rosin oil and sulphuric acid should not be 

 used in proprietary insecticides. 



SPRAYS FOR RED SPIDERS AND RUST MITES. 



It has been known for many years that sulphur sprays are success- 

 ful against both rust mites and red spiders. Lime-sulphur solution 

 is no doubt the best form of sulphur which has ever been devised for 

 the control of these pests. The main value of this solution over other 

 forms consists in its permanency, since after it once dries on the 

 leaves it remains for a considerable length of time, whereas other 



