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HORTICULTURAL SOCIETY OF NEW YORK. 



lected it upon this host in this State. The fact that this fungus has occurred 

 so abundantly upon this chance seedling, coupled with the other characters, 

 leaves no doubt in my mind as to thehybrid origin of the seeding. (Since 

 writing the above the writer has found the fungus in the red raspberry.) 



Plum Hybrids and Diseases. For some years plum scab (Clado- 

 sporium carpophilum) has been abundant upon different varieties of the 

 Prunus Americana. It is true that some years it is much more abundant 

 than others, some years being so common as to seriously affect the market 

 value of plums. The writer has never seen this fungus upon the European 

 Prunus domcstica or the Japan plum. Some varieties of the American plum 

 are much more seriously affected than others. I was, therefore, very much 

 interested in finding that certain hybrid varieties of the P. Americatui crossed 

 with the Japan plum had some of the plum scab. Of the seedlings obtained 

 from the same experiments there are some varieties of the hybrids that are 

 exempt, but in one variety the disease occurred successively for several years. 



The Wild Crab. In our State the wild crab is seriously affected 

 with several fungus diseases, notablj' the cedar apple fungus (Rocstelia 

 pyrata) and the apple scab (Fusicladium dcndriticum) . Some varieties of 

 Pyrus malus are also commonly affected with the apple scab, but never, so far 

 as I know, with the cedar apple fungus. The Soulard crab, which is generally 

 now regarded as a hybrid between the Pyrus malus and the Pyrus loivensis, 

 is usually free from the Roestelia, though occasionally I have seen a few dis- 

 eased leaves when in proximity to the red cedar. It is also slightly affected 

 with the apple scab fungus. The Mercer County crab, which by some writers 

 has been regarded as a good form of Pyrus lozicnsis, and by others has been 

 regarded as a hybrid, and I am inclined to this latter view. It is very 

 different with respect to its diseases from the Soulard crab. I have 

 had a tree of this variety under observation for eleven years, and he has 

 watched from year to year in a general way the amount of fungus diseases 

 affecting the fruit and leaves. In most seasons it is nothing unusual to find 

 that a large number of the leaves are affected with the Roestelia pyrata. 

 During all this time the writer has never seen this fungus upon the fruit or 

 branches, and yet it has been very common upon both fruit and branches 

 upon our wild crab. Apple scab is rather rare on the fruit, only occurring 

 upon the leaves.* 



Gooseberries. The native wild goosberries in this State, both the 

 Ribes gracile and R. Cynosbati, are seriously affected with the gooseberry rust 

 (Accidium grossulariece) . Taking the Champion as a type of the cultivated 

 species of the European Ribes grossularicc is not affected, at least not seri- 

 ously, with this fungus. A hybrid of this species and the R. gracile had a 

 few diseased leaves and fruit the past spring, but generally speaking it is 

 quite free from this fungus. In regard to the Septoria Ribis occurring upon 

 both the wild species and the cultivated, I may say that the past season has 

 been extremely detrimental to the gooseberries, the leaves falling off prema- 

 turely. The hybrid has retained its leaves much longer than the cultivated 

 gooseberry, indicating that the hybrid is superior in the quality of resistance 

 to plant diseases as compared with the cultivated forms. 



In order that we may look up this matter a little more, I hope that 

 anyone interested will give to me such information as he may have on this 

 subject, and shall be greatly obliged if I could receive specimens. 



*Hume and Craig. Native Crab Apples nnd Their Cultivated Varieties. Proc. Iowa 

 Acad. Sci. 7: 123. 



