Fungicides 443 



Lime-sulfur. ^^^ — This fungicide (the material is also 

 used in the control of San Jose scale) is prepared by boiling, 

 in water, lime and sulfur in the proportion of approximately 

 two parts of sulfur to one of lime. The products in the 

 resulting solution are calcium thiosulfate (CaSoOs), calcium 

 tetrasulfid (CaSi), and calcium pentasulfid (CaSs). The 

 material may be made by the orchardist or bought from 

 manufacturers. The commercial product is more concen- 

 trated than that made by the formulas usually recom- 

 mended for home use, and contains a higher proportion 

 of polysulfid sulfur (that is, sulfur in the form of CaS4 

 and CaSa). 



The combination of constituents ^^^ that appears best to 

 meet the largest number of desirable conditions is the follow- 

 ing, stated in round numbers: 



36 pounds of lime (pure lime, CaO, used as a basis). 

 80 pounds of high grade, finely divided sulfur. 

 50 gallons of water. 



When lime containing impurities is used, more than 36 

 pounds must be taken in order to obtain 36 pounds of pure 

 lime. 



Use 38 pounds of lime containing 5 per cent of impurities 

 (95 per cent pure). 



Use 40 pounds of lime containing 10 per cent impurities 

 (90 per cent pure). 



No lime should be used which contains more than 10 per 

 cent of impurities. If the lime contains impurities (oxid of 

 magnesium, iron, aluminum, etc., and carbonates of mag- 

 nesium, calcium, etc.), these do not go into solution but re- 

 main as sediment, together with any undissolved sulfur 

 not acted upon because of insufficiency of pure lime, due to 

 impurities in the lime used. The amount of sediment thus 

 formed can be utilized as a measure of the amount of im- 

 purities existing in the lime. 



The level of the mixture during l^oiling should be kept near 

 the 50-gallon mark — not being allowed to drop more than an 



