238 THE APPLE 



pound ; of the lime, from '$ to i cent per pound ; and of labor, 

 from 30 to 60 cents per barrel. 



The solution obtained by following the above directions should 

 never be used at full strength, but should be diluted with water, 

 the amount depending on its density and the condition of the trees 

 to which it is to be applied. If directions are carefully followed, 

 a solution should be obtained having a specific gravity between 

 1.24 and 1.27. Mixtures prepared with exactly the same grade 

 of materials may vary somewhat in density, and it is necessary to 

 have a means of testing them. Accurate tests may be made with 

 a hydrometer having a specific-gravity scale, it being essential of 

 course to use an instrument made for testing liquids heavier than 

 water. A hydrometer for testing lime-sulphur should have a scale 

 ranging from 1.00 to 1.32 or 1.35 specific gravity. 



A lime-sulphur mixture having a specific gravity of 1.03 will 

 control the San Jose scale, and therefore is efficient for all appli- 

 cations made when the trees are dormant. For spraying apple and 

 pear trees in foliage, it is not safe to use this mixture at a strength 

 greater than 1.01 specific gravity. 



To determine the proper amount of water to use with each gallon 

 of a home-boiled or commercial concentrated lime-sulphur mixture, 

 divide the decimal of the specific gravity of the concentrate by the 

 decimal of the desired spray. For example, if the specific gravity 

 reading of the concentrate is 1 .24, divide .24 by .03 to get a spray 

 of 1 .03 specific gravity. The result is 8, which is the number of 

 dilutions required. In other words, in every 8 gallons of spray 

 mixture there should be 1 gallon of concentrate and 7 gallons of 

 water. This means that in 50 gallons of spray solution there should 

 be 6\ gallons of concentrate and 43? gallons of water. 



Bordeaux mixture. This material is being used less and less 

 each year in orchard spraying. So much fruit has been russeted 

 and so much foliage burned by it that growers have generally taken 

 lime-sulphur as a substitute. It is still used to a certain extent, 

 however, and gives good results in some cases. 



The formula 3-3-50 is used more than any other in orchard 

 work. An excess of lime is not recommended, as it causes a slower 

 action, clogs the machinery to some extent, causes an uneven appli- 

 cation, and is more readily washed from the trees. In wet seasons 



