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N. Y, Virus and Virus-Like Diseases of Tree Fruits . — 2. Diseases 



(Cornell) of Flum , To learn (1 & 2) nature of leaf-casting mottle of 



Fellenberg and bud -union constriction disease of Stanley prune 

 so as to devise control method, nature of so-called asteroid 

 spot of Myrobalan rootstock and its relation to constriction 

 disease of Stanley prune and reduction in growth of other 

 varieties; (3) establish budwood sources of Fellenberg free 

 from leaf-casting mottle and establish Wyrobalan seed-producing 

 trees free from asteroid. 



PI. Path., Pomol. 134-2 (IIE-IA) 



N. Y. Virus and Virus-Like Diseases of Tree Fruits. — 3« Sour 



(Cornell) Cherry Yellows and Ring Spot of Stone Fruits , (l) Learn amount 

 of damage by viruses in different species and varieties of 

 stone fruits growing commercially in State, and compare sus- 

 ceptibility of different varieties of each species to viruses; 



(2) select the more resistant varieties for breeding stock; 



(3) learn relation of viruses to each other and other viruses; 



(4) learn influence of different rootstocks on disease effects; 



(5) learn relation of environmental conditions including soil 

 factors and tree nutrition, to effects of diseases; (6) learn 

 rate of spread in field in relation to variable environmental 

 conditions with respect to cover crops, weeds, other tree 

 species, and different climatic conditions; (7) use cross- 

 protection tests to obtain information on relationships of 

 viruses, and data on use of cross-protection. 



PI. Path., Pomol. 134-3 (NE-14) 



N. Y. Virus and Virus-Like Diseases of Tree Fruits. — 4« Produc- 



( Cornell ) tion and Maintenance of Virus-Free Nursery Foundation Stock of 

 Commercial Fruit Varieties . (l) Produce and maintain virus- 

 free clones of various species and varieties of fruit trees, 

 and establish healthy seed source trees for rootstock production; 

 (2) improve present methods of indexing for determination of 

 freedom from viruses. 



PI. Path., Pomol. 134 -A (NE^14) 



N. Y. Virus and Virus-Like Diseases of Tree Fruit. — 5» Trans- 



( Cornell) mission of Vims es that Affect Tree Fruits, and Their Insect 

 Vectors . (l) Find and identify vector (s) of each of several 

 important viruses causing diseases in stone fruits. Study 

 insects to learn means of application of control measures. 

 Study insect transmission which provides means of separating 

 virus complexes. 



Ent., PI. Path., Pomol. 134-5 (NE-IA) 



