59t^ 



Bulletin 283. 



Concentrated 



commercial 



lime-sulfur 



washes. 



This mixture can be applied safely only when the trees are dormant — late in 

 the autumn after the leaves have fallen, or early in the spring before the buds 

 swell. As the San Jos6 scale is not killed unless the solution comes in contact 

 with it, great care should be exercised to completely cover the branches. 



Within the past few years, commercial concentrated lime- 

 sulfur solutions have been introduced into this State and have 

 been used quite extensively by many fruit growers in combating 

 certain insect pests and fungous diseases. Careful and exten- 

 sive experiments have shown that these mixtures when thor- 

 oughly applied will give very satisfactory results in controlling 

 the San Jos^ scale and the blister mite. For the control of these two pests the 

 washes are applied only during the dormant period of the infested trees. 



Unfortunately it seems impossible to manufacture a standard unvariable mixture 

 and we therefore find the different brands varying considerably in their chemical 

 and physical composition, although the solutions put on the market during the 

 season of 1910 showed much less variation than those sold during previous years. 

 In order to use one of these mixtures intelligently and effectively it becomes 

 necessary to know its strength or, in other words, its degree of concentration. 

 This is best found by using an instrument known as a Beaum6 hydrometer. An 

 accurate hydrometer may be purchased through your local druggist. The instru- 

 ment should range from about 25 degrees to 35 degrees. In testing a lime-sulfur 

 solution, simply pour some of the clear reddish liquid into any deep receptacle, 

 deeper than the hydrometer is long, and when full gently drop the instrument 

 into the solution and wait until it comes to rest. Then read on the hydrometer 

 the degree of concentration, which will be the one just at the surface of the liquid. 

 When the degree of concentration of the solution is known, the proper dilution 

 may be obtained by referring to the following tables computed by Mr. P. J. Parrott 

 of the Geneva Experiment Station (Geneva Bulletin 320): 



