320 Plums and Plum Culture 



the diseased fruits do not fall from the trees, but shrivel 

 and blacken and remain hanging to the dead or dying 

 fruit spur all the winter through. These mummied 

 fruits are perfect masses of fungus spores. 



The dark-colored spores formed at this season are 

 able to live over winter in perfect condition for the re- 

 newal of the fungous growth the succeeding spring. It 

 becomes an important preventive measure, therefore, to 

 destroy these spore-infested mummied fruits, the rotted 

 fruits on the ground, and the dead twigs in the tree. 

 The dead parts should be cut out and burned; and the 

 dried or rotted fruits should be carefully gathered and 

 likewise cremated. This is important and worth while. 

 Such treatment followed by proper spraying will prac- 

 tically eliminate the monilia from the list of plum 

 troubles. 



The same disease works on peaches, apricots and 

 cherries. It is desirable, therefore, in treating plums, 

 to extend the same preventive and remedial measures 

 to all other stone fruits in the same orchard. 



Black knot. This disease, which rejoices in the 

 scientific name of Ploivrightia morbosa, is especially 

 bad in neglected orchards, and in trees growing along 

 roadsides. In these trees, outside cultivation, it fairly 

 revels. Here it breeds, and from here it spreads to 

 neighboring orchards. It occurs on all sorts of plums 

 (contrary to the statements of the tree peddler), some- 

 times on the cherry, and often on wild trees of black 

 cherry and choke cherry. 



It is worse on some varieties of plums than on 

 others, but this difference is not marked. When the 

 Japanese plums were all novelties in this country it 

 was freely claimed that they were proof against black 

 knot. They are not. They are, perhaps, less suscep- 

 tible to its attacks than some other plums are; but this 

 difference of susceptibility is not sufficiently marked 



