APPLE GROWING IN CALIFORNIA. 95 



County Commissioner of Santa Cruz County, the winter is spent both 

 in dormant buds and as spores in black patches on the twigs. The 

 disease may be started in the spring from the fungus in the dormant 

 buds or from these black patches on the twigs, the former being the 

 common source of infestation in the Pajaro Valley. The climatic condi- 

 tions of that section are said to favor very greatly the development of 

 the disease. At high altitudes, wherever apples are grown, serious infes- 

 tations have been found. Here again moisture conditions are such as 

 to aggravate the trouble. The authors of the previously mentioned bul- 

 letin recommend finely divided sulphur in some form as the very best 

 mildew fungicide. Ordinary flowers of sulphur is not fine enough for 

 good results. The following instructions and formula are copied from 

 their bulletin and this formula has given general satisfaction wherever 

 it has been tested out : 



Preparation of the Iron-Sulphid Mixture. 



The following directions are for the preparation of sufficient stock iron-sulphid 

 mixture to make 500 gallons of spray : Fill a 50-gallon barrel about two thirds full 

 of water. Weigh out 10 pounds of iron sulphate (copperas), place in a 'sack, and 

 suspend in the water. The iron sulphate will dissolve fairly rapidly, and when it is 

 all in solution measure out carefully 2 gallons of commercial lime-sulphur solution 

 testing 33 Baume", or 2 gallons and 3 pints of a lime-sulphur solution testing 32 

 liaium''. Slowly pour all but 2 pints of the lime-sulphur solution into the iron- 

 sulphate solution in the barrel, stirring the mixture vigorously with a hoe or shovel. 

 The addition of the lime-sulphur solution will produce a bulky, black precipitate, and 

 when all but 2 pints of the lime-sulphur solution has been added the mixture should 

 be allowed to stand for a few minutes, when the black precipitate will begin to settle 

 and a little of the clear liquid at the top can be carefully dipped out with a clean 

 glass or cup. This clear liquid will probably show no yellow lime-sulphur color, 

 which means that an excess of lime-sulphur solution has not yet been added. In 

 other woids, there is still some iron sulphate in solution, in which case the addition 

 of a drop of lime-sulphur solution to the clear liquid in the glass will produce a black 

 precipitate. This means that more lime-sulphur solution should be added to the stock 

 in the barrel, and about half of the remaining 2 pints should now be poured in and 

 the contents of the barrel stirred vigorously and allowed to stand. Some of the 

 clear liquid should again be dipped off and tested as before, to determine whether an 

 '.v.-ss of lime-sulphur solution has been added. If necessary, the addition of small 

 quantities of lime-sulphur solution should be continued until some of the clear liquid 

 dipped from the top, after the contents of the barrel have been well stirred and 

 allowed to settle, shows a pale yellowish lime-sulphur tint. The purpose of using 

 n slight excess of the lime-sulphur solution is to insure all the iron sulphate being 

 utilized. The voluminous black precipitate that is formed consists of iron sulphid. 

 precipitated sulphur, and calcium sulphate. After a slight excess of lime-sulphur 

 solution has been added, the barrel should be filled with water and the contents stirred 

 thoroughly and allowed to stand for several hours. The black iron-sulphid mixture 

 will settle into the lower half or third of the barrel, and the clear liquid should be 

 P'.iu-f'd off by carefully and gradually tipping the barrel, without allowing any of the 

 f.iack precipitate to run out. The barrel should again be filled with water, the 

 contents thoroughly stirred and allowed to stand several hours, and the clear liquid 

 poured off as before. This operation of washing the precipitate should be repeated 

 until the water poured off no longer shows the yellow lime-sulphur tinge. Probably 

 three or more such washings will be required, depending upon how careful the operator 

 has been in using only a slight excess of lime-sulphur solution. 



It is evident that the preparation of this stock supply should be commenced two or 

 three days before the spraying is to be done, but when once prepared it may be kept 

 indefinitely. If care is used in weighing out each lot of iron sulphate and if the 

 lime-sulphur solution used is accurately measured there will be no trouble in making 



