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W. Va. Virus Diseases of Sour Cherry and Other Stone Fruits . To 

 learn (1) rate of spread of cherry virus diseases; (2) method 

 of spread of stone fruit viruses in general -with reference to 

 possible insect vectors of cheriy yellows and ringspot; (3) 

 effect on yield and tree growth caused by viruses of sour 

 cherry; (A) attempt to locate virus-free sources of Mazzard 

 cherry seed for conmercial propagation, 

 Hort., PI. Path. 89 (NE-IA) 



Wis, Stone Fruit Virus Diseases and Their Control , To develop 



a basis and methods for effective control of stone fruit virus 

 diseases, with special reference to those that occur in 

 Wisconsin or are thought to be a menance to Wisconsin in stone 

 fruit culture. 



PI. Path. 301b (NC-IA) Coop. ARS 



Citrus and Other Subtropical Fruits 



Ariz. Control of Root Diseases and Virus Diseases of Citrus , (l) 



Perfect methods of protection from, and control of, dry-root 

 rot of citrus; (2) treat trees infested by citrus nematodes by 

 eradication or control of nematodes; disinfect soils of citrus 

 nematodes before replanting; (3) establish sources of budwood 

 of superior varieties of lemons and other citrus which can be 

 certified as free from virus or other infectious diseases. 

 PI. Path. 222 



Ariz, Wood-Necrosis Gummosis of Citrus , To learn (l) organism 

 or agent causing Wood-necrosis Gummosis in Arizona; (2) field 

 or laboratory symp tons which can be relied upon to distinguish 

 Wood -necrosis IXunmosis from all similar diseases; (3) effect 

 of disease on yield, fruit quality, rate of growth and longev- 

 ity of Marsh Seedless grapefruit; (4) develop methods of pro- 

 tecting citrus trees from infection; (5) method for treating 

 infected trees. 



PI. Path. 407 Coop. ARS 



Calif. Effect of Water and Nutrient Level on Development of 



Omphalia Root Rot of the Date Palm ^ To (1) determine effect 

 of 2 levels of soil moisture and 2 to 4 levels of nutrition 

 on development of Omphalia root rot in controlled inoculation 

 experiments, as there is evidence that adequate water and 

 perhaps nutrients will minimize injurious effects of Omphalia ; 



(2) answer such questions as: extent of injury to commercial 

 palms inoculated with Omphalia , is harmful effect minimized 



when trees received adequate water and nutrients, or accentuated 

 when they receive inadequate water and nutrients, etc., and 



(3) continue to maintain Mecca plot for at least 5 more years, 



PI. Path. 878-A 



