96 APPLE GROWING IN CALIFORNIA. 



up the stock supplies rapidly after the first two or three batches have been prepared, 

 and it will be remembered that each batch is sufficient for making 500 gallons of 

 spray mixture. In order to keep a supply of the stock mixture on hand, several 

 britches should be prepared before the spraying commences, and as rapidly as a barrel 

 is emptied the preparation of a new batch should be started. Iron sulphate is com- 

 paratively cheap, and the entire cost of materials for preparing 100 gallons of the 

 mildew spray, when diluted according to the recommendations given in this bulletin, 

 should not exceed 15 or 20 cents. 



When the washing has been completed, the stock barrel should be filled with water 

 to exactly 50 gallons. The material is now ready for use as directed under "General 

 formula for the spray mixture," but care should be taken to stir the contents of the 

 barrel thoroughly each time before any of the mixture is taken out. 



General Formula for the Spray Mixture. 



Stock iron-sulphid mixture 20 gallons 



Arsenicals and nicotine solution to te added as required. 

 Water, to make 200 gallons 



When arsenicals and a nicotine solution are to be used in conjunction with the 

 ii-on-sulphid mixture, the combined spray may be prepared by first running about 150 

 or 160 gallons of water into the spray tank. The agitator is then started and the 

 20 gallons of stock iron-sulphid mixture is poured in, after which the nicotine solution 

 and the arsenicals may be added in the usual way. Sufficient water should then be 

 added to make 200 gallons. 



This same strength of iron-sulphid mixture, namely, 20 gallons in 200 gallons of 

 spray, is to be used in all the mildew applications. It will be seen that the 20 gallons 

 of stock mixture used in each 200 gallons of spray contains the product from 4 

 pounds of iron sulphate. 



There are other products besides iron-sulphid which contain sulphur 

 in a very finely divided form that can be used just as effectively in the 

 control of mildew. The California Spray Chemical Company at Wat- 

 son ville is supplying a form known as ' ' Milled Sulphur, ' ' and both the 

 General Chemical Company and Balfour, Guthrie & Co., of San Fran- 

 cisco, sell another product under the trade name of ' * Atomic Sulphur. ' ' 

 No doubt there are still other forms that could be used to good advan- 

 tage, the essential qualifications being the finely divided state of the 

 sulphur, as has already been indicated. 



As is true with most diseases of this nature, a thrifty, strong growing 

 tree is apt to resist attacks to a greater or less extent. Consequently, it 

 is very desirable that everything be done toward keeping orchards in the 

 best possible condition. Thus fertilization may be a great benefit, and 

 Ballard and Volck recommend spraying during the early spring with a 

 crude oil emulsion, which has a tendency to stimulate growth. Pruning 

 is an important means of checking this disease. All infested twigs which 

 are noticed during the time of pruning, either in the dormant or sum- 

 mer season, should be cut from the trees. 



