ISTew York Agricultural Experiment Station. 421 



that the trees be sprayed just before blossoming and again imme- 

 diately after the blossoms fall, but no line of treatment is recom- 

 mended. 



PowelP*^' recommends picking the fruit before it is fully ripe; 

 that is, before it softens. 



LEAF-SPOT, 



{Cylindros'porm'ni padi Karst.) 



Description. — The leaf-spot of cherry, plum and apricot, which 

 is caused by the fungus named above, at first appears as minute 

 spots on the leaf, a sixteenth of an inch or less in diameter. On 

 cherry and plum especially, the spots may have a reddish-tinged 

 margin. Afterwards they increase in size and may enlarge to an 

 eighth of an inch or more across. The spots soon become dark 

 brown with a pale center, and in many cases the diseased tissue 

 loosens and drops out leaving a clean-cut hole in the leaf. For 

 this reason the disease is sometimes called the " shot-hole dis- 

 ease."^" The disease may cause serious injury for sometimes the 

 trees are nearly defoliated by it. Should this occur when the 

 trees are heavily loaded with fruit, as it is especially apt to do 

 with plums, the trees may be much weakened in vitality ^^ and con- 

 sequently more liable to winter injury. 



Treatment. — It has been shown conclusively that the leaf blight 

 may be controlled by proper treatment with Bordeaux mixture 

 but in cherrv orchards the treatments cannot be made at the most 

 favorable time for controlling the disease because the spray mix- 

 tures adhere to the fruit and injure its market value.^^ From our 

 present knowledge of the subject no line of treatment can be 

 positively recommended for bearing cherry trees, but it is sug- 



16 Powell, G. Harold. Del. Ag;r. Exp. Sta. Kept. 1897: 193. 



iTDuggar has shown that a shot-hole appearance in plum and peach foliage 

 is not always due to fungous attacks, but may be caused by other injuries, 

 notably by spraying with improperly prepared mixtures. See Proe. Soc. for 

 Promotion Agr. Science, 1898, and Cornell Agr. Exp. Sta. Bui. 164: 385. 



18 Beach. Annual Eept. this Station, 1896: 385; also Bulletin 98. 



19 Beach. Annual Kept, this Station, 1896: 406. 



