Drupaceous Fruits 101 



symptom showing first on single branches and extending 

 year by year till the whole tree is involved. The twigs first 

 infected soon die, and in the course of a few years the whole 

 tree usually succumbs. The wood of diseased branches is 

 browned. The sporophores of the Stereum, which appears 

 to be the usual causal agent, develop only after the death 

 of the tree. The disease is most common on plum and other 

 drupes, but is known also on apple, pear, currant, goose- 

 berry, chestnut, and ash. 



Brown-rot {Sclerotinia dnerea, Monilia). — Brown-rot is 

 serious on the plum as it is with the peach and cherr3^ The 

 loss in Ohio in one year was estimated at $25,000. 



For description and treatment, see peach. 



Minor diseases 



Blight ^^'^ {Bacillus amylovorus). — Blight of the apple 

 and pear has been discussed on preceding pages. A similar 

 blight is rarely known to affect the plum tree, and careful 

 studies by Jones show that the diseases on plum and pear are 

 identical. For treatment, see pear. For Powdery-mildew, 

 see cherry. Crown-gall, Armillaria root-rot, Rust, Black- 

 spot (Pseudomonas primi), see peach. Yellows and Rosette 

 are less injurious than on peach; Little-plum is similar to 

 Little-peach. 



