OIDIUM OR POWDERY MILDEW OF T"HE VINE. 333 



If the distribution is defective, we not only fail to free* all parts of 

 the vine from the Oidium but we leave enough of the fungus to spread 

 rapidly through the vineyard as soon as the sulfur has been removed 

 by rain or wind. Two or three incomplete sulfurings which fail to 

 reach a number of whole vines or parts of vines are often less effective 

 than one thorough treatment which leaves no part of any vinje un- 

 touched. 



The methods used in California for sulfuring vines are the fol- 

 lowing : 



1. Throwing the sulfur on the vines by hand; 



2. Distributing by perforated cans of various forms ; 



3. Shaking through the tissue of a cloth sack ; 



4. Various forms of hand bellows ; 



5. Various forms of knapsack bellows ; 



6. Traction sulfur distributers. 



The disease can be completely controlled by any of these methods. 

 They differ only in the amount of labor, sulfur, and care necessary in 

 applying them. In these respects, however, they differ very notably. 



1. Throwing on by hand is undoubtedly the most laborious, dis- 

 agreeable, and wasteful. Something like 90 per cent, or more of the 

 sulfur is wasted because most of it goes on the ground, and of that 

 which goes on the vine a few leaves usually receive the bulk. When 

 the vines are large, if all parts of the vine, extremities of canes and 

 center of head, are properly treated, from five to twenty times as much 

 sulfur will be used as by the best methods. It also requires more time 

 than the better methods. It is moreover very difficult to get men to 

 sulfur effectively by this means owing to the large amount of sulfur 

 they get into their eyes and mouths. They are naturally apt to think 

 more of protecting themselves than of destroying the mildew. 



2. Distribution from perforated cans is perhaps the commonest 

 method of application. It is a little better than hand throwing, but 

 wastes a great deal of sulfur. With large vines from five to ten times 

 as much is used as is necessary. It is very difficult to reach the tops of 

 high vines with the ordinary forms of cans. Some sulfur cans are 

 made with a long handle, which obviate this defect to some extent but 

 increase the difficulty of sulfuring the low parts and center of the vine. 



In both these methods it is unnecessary to use the best brands of 

 sulfur, as with complete distribution so much is used that there is 

 always enough fine material, except with the worst grades, to do the 

 work. Some growers mix the sulfur with lime, ashes, road dust, or 

 some inert powder to save sulfur. The main objection to this is that 

 it involves the carrying and distribution of useless material. 



