154 MANUAL OF FRUIT DISEASES 



as the fruit is setting, and (2) later, depending on the amount 

 of rain. In seasons of brief shower-periods followed by drying 

 weather, spraying is regarded as unnecessary. (Brown-rot is 

 more fully discussed under Peach, page 27CO 



FROST-INJURY 

 Caused by the action of low temperatures 



Like other fruit-trees, the apricot suffers from the effects of 

 frost. Injury by low temperatures in winter, winter-injury, is 

 perhaps the most destructive of all apricot troubles. Collar- 

 rot, or crown-rot, is particularly common and injurious. (For 

 fuller discussion and additional references see under Apple, 

 page 35.) 



REFERENCE 



Stewart, F. C., Rolfs, F. M., and Hall, F. H. A fruit-disease survey 

 of western New York in 1900. Apricot diseases. Collar rot. 

 New York (Geneva) Agr. Exp. Sta. Bui. 191 : 303-304. 1900. 



SCAB 



Caused by Cladosporium carpophilum Thiim. 



The scab disease, or freckle as it is often called, occurs on 

 stone-fruits other, than the apricot. In fact it affects the peach 

 very commonly. Black scab spots are produced on the fruits 

 and pale-gray blotches with dark margins are developed on the 

 twigs. The first record of the disease on apricot in California 

 dates back to 1909. While it has attracted some attention in 

 that state, yet it is said to have never been sufficiently trouble- 

 some to warrant treatment. It has been found abundantly 

 in Connecticut and Texas. (Fuller discussion under Peach, 

 page 294.) 



