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Utah Virus and Vims-Like Diseases of Stone Fruits , To (l) 



identify and characterize the virus and virus-like diseases 

 responsible for the degeneration of stone fruit orchards of 

 Utah; (2) discover host ranges and symptom expressions of 

 the various viruses in Utah's stone fruits; (3) learn etiology 

 of little-understood stone fruit diseases; (4) learn the physical, 

 chemical, and biological properties of the various stone fruit 

 viruses; (5) devise diagnostic tests for the various stone fruit 

 viruses in different suscepts; (6) learn insect vectors and other 

 means of natural dissemination of the stone fruit viruses; (?) 

 perfect effective means of economic control of these virus diseases; 

 (8) select and propagate virus-free clones of important com- 

 mercial varieties of stone fruits and their rootstocks on their 

 ovm roots; and (9) grow these virus-free selections in an isolated 

 repository plot at Logan from which they will be made available 

 to the nursery industry for the establishment of budwood mother 

 blocks • 



PI. Path., Bot. 318, Coop. ABC 



Utah The Physical and Chemical Properties of Ring Spot. Sour 



Cherry Yellows and Prune Dwarf Virus esT To (1) isolate viruses 

 causing ringspot^ sour cherry yellows and prune dwarf diseases 

 of stone fruits; (2) learn size, shape, isoelectric point, and 

 chemical composition of isolated viruses; and (3) attempt to 

 demonstrate infectivity of these viruses on suitable susceptible 

 host plants, 



Bot. 466 (W-22) 



Wash. Determine the Prevalence of Sour Cherry Yellows and Ring 

 Spot Viruses in Mazzard. Mahaleb and Miyrobalan Seed Sources in 

 the Pacific Northwest . To determine the prevalence of sour 

 cherry yellows and ring spot viruses in Mazzard, Mahaleb, and 

 Jfyrob§lan seed sources in the Pacific Northwest and to establish 

 seed sources free of these diseases for experimental and com- 

 mercial use. 



Pl.Path. 1232 (W-22) 



Wash. Obtaining and Preserving Virus-Free Deciduous Tree Fruit 

 Stocks . To outline and designate the responsibilites of the 

 agencies (Dept. of Plant Pathology, Irrigation Exp. Station, 

 Plant Introduction and Quarantine Station, Washington State 

 Department of Agriculture) relative to the operation of project 

 IR-2 



PI. Path. 1262 (IR-2) Coop. ARS 



