64 



FUXGI AND FUXGICIDES 



disease. Yarious names of fungi have been used in 

 connection with it, one of the commonest being Septoria 

 cerasina. The name printed above is the one now 

 accepted by botanists. 



The leaf-blight is especially destructive in the nur- 

 sery, the young trees often 

 being defoliated before the 

 middle of August. Bear- 

 ing jilum trees also lose 

 their leaves prematurely 

 on account of it. 



Treatment. — Exper- 

 iments conducted on an 

 extensive scale by the Ohio 

 Experiment Station show 

 that in the orchard this 

 disease may be prevented 

 by spraying with dilute 

 Bordeaux mixture. Two 

 or three sprayings early in 

 the season are deemed suffi- 

 cient. It should not be 

 used too late, on account 

 of the liability of the mix- 

 ture to remain on the 

 ripened fruit. In the nur- 

 sery the Bordeaux mixture 

 is also a preventive ; the 

 results of its use are well 

 represented in Fig. 34, re- 

 duced from photographic 

 views of experiments conducted by the Division of 

 Vegetable Pathology. 



Literature. — This disease has frequently been dis- 

 cussed in our horticultural literature, although very 

 little of value concerning remedies has been published 



FIG. 33. DISEASED PLUM LEAF. 



