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 RBGICNAL PROJECTS 



IR-2 Obtaining and Preserving Virus-Free Deciduous Tree Frtdt 



Stocks , (1) To assemble all apparently virus-free selections of 

 desirable species and varieties of deciduous tree fruit stocks and, 

 when verified to be free of viruses by accepted indexing procedures, 

 to establish and maintain them in isolated repositories; (2) to 

 establish a research unit designed to study present indexing techniques 

 for virus detection and attempt to develop better or more efficient 

 methods; (3) to study possible methods of eliminating viruses from 

 contaminated stock where clean propagating material is not available; 

 (a) to distribute uniform viruB-free propagating materials for 

 foundation stock to cooperating investigators for use in research or 

 for release to the industry. 



Cooperating stations and agencies: Federal-grant project - 

 Wash., ARS 



NC-IA Stone Fruit Virus Diseases and Their Control , (l) To 



detemdne the occurrence and geographical range of stone finiit 

 virus diseases and their variations in symptom expression on 

 different hosts and under different climatic conditions in the 

 North Central Region; (2) to devise reliable methods of detecting 

 the presence of latent viruses in stone fruits and to determine 

 their distribution in the North Central Region; (3) to separate 

 and identify the stone fruit virus entities present in the North 

 Central Region and to determine their ability to incite disease 

 singly and in combinations; (A) to determine the host ranges and 

 the modes of transmission and dissemination of the viruses of 

 stone fruits and to acquire other essential information; (5) 

 to devise economical and effective measures for the control of 

 stone fruit virus diseases in the North Central Region. 



Cooperating stations and agencies: Federal-grant projects - 

 111., Ind., Iowa, Mich., Minn., ffo., Nebr., Ohio, Wise, 

 ARS 



NE-IA Virus Diseases of Deciduous Tree Fruits and Their Control , 



(l) To establish the virus entity or entities inciting specific 

 diseases of deciduous tree fruits and to determine their relation- 

 ship and economic im.portance; (2) to determine the epidemiology 

 of such virus diseases and to identify their principal vectors j 

 (3) to devise practicable and economic methods of deciduous 

 fruit virus diseases. 



Cooperating stations and agencies: Federal-grant projects - 

 Maine, N. H., N. Y. (Cornell), N.T. (Geneva), Pa., W. Va. 



W-22 Behavior aiKJ Effects of the Virus Complexes Latent in Stone 



Fruit Varieties and Rootstocks . To determine the presence, effects, 

 and interaction of latent and symptom-expressing viruses in stone 

 fruit stocks. 



Cooperating stations and agencies: Federal-grant projects - 

 Calif., Colo., Idaho, Mont., Oreg., Utah, Wash., ARS 



