258 Peach-Growing 



twigs may be somewhat weakened by the disease, but the 

 injm-y is evidently very slight. 



"The results of spraying experiments indicate that fruit 

 infections begin to take place from three to four weeks 

 after the petals fall, although the spots do not appear until 

 about three weeks later. In some experiments spraying 

 with a fungicide four weeks after the petals fell almost 

 completely prevented the disease, while a similar treatment 

 one week later on an adjacent plot of the same variety was 

 only about half as effective. Infections may continue 

 to take place until about a month before the fruit ripens. 

 It is a green fruit disease, however, and it is doubtful whether 

 the nearly mature fruit is susceptible.'' 



There is a wide difference in the susceptibility of varie- 

 ties to scab, though none is immune. In general the later 

 varieties are more seriously affected than early sorts, but 

 this may be due to the course of development rather than 

 the direct result of partial resistance. 



Methods of control of scab. 



The self-boiled lime-sulfur mixture is practically a specific 

 for this disease. Directions for making the applications 

 are found in the spraying program on pages 285-286. 



Leaf-curl {Exoascus deformans) 



Peach leaf-curl is widely disseminated, occurring more or 

 less in practically all peach-growing regions of the country, 

 but more especially perhaps in the northern districts. As 

 the name implies, this disease affects the leaves, causing 

 them to become very much thickened and greatly dis- 

 torted. The twigs, also the fruit, may be attacked ; but the 



