- 13 - 



Calif • Insect Vectors and Their Relation to Virus Diseases of 



Ornamental Plants . (l) Learn vectors of viruses of ornamental 

 plants; (2) investigate such vector- virus relationships as: 

 acquisition and inoculation feeding thresholds, persistence and 

 non-persistence of viruses in vectors, differential efficiency 

 among vectors; (3) identify respective viruses occurring in 

 orchids; (k) learn relationship of orchid viruses by serology, 

 hosts, symptoms, properties, electron microscopy, and vectors; 

 (5) describe symptoms caused by single viruses in various orchid 

 genera; (6) study host range of orchid viruses; (7) investigate 

 control of orchid viruses, 

 Ent. & Parasitol. 1365 C 



Calif. Investigation of the Nature of the Virus Diseases of Cereals 



and Leguminous Crops in California with Reference to Transmission, 

 Variability. Effect on Yield. Host Range and Varietal Reaction . 

 To learn (1) interrelation of recognized viruses of wheat, oats 

 and barley; (2) nature of other viruses and virus- like diseases 

 of cereals and grasses and their relation to native and cultivated 

 grasses; (3) viruses in alfalfa, clovers and other legumes by 

 identification; (A) methods of dissemination and relative economic 

 importance of viruses upon legumes being grown for forage and seed 

 production; (5) correlate studies with Agronomy Department. 

 PI. Path. 1652 Coop. FES 



Calif. Soil-Borne Viruses - Mode of Infection and Survival in the 



Absence of the Specific Host or Hosts . (1) Utilize known methods 

 or develop methods of isolating the respective viruses in pure 

 state; (2) learn methods of survival of viruses in different soil 

 types; (3) study reaction of soil-borne viruses to soil microflora; 

 (A) learn mechanism of transmission from soil to host; (5) longevity 

 of different virus types under varying soil conditions; (6) from 

 above findings, formulate an effective control or eradicant recom- 

 mendation for different types of soil-borne viruses. 

 PI. Path. 1715 Coop. ARS 



Fla. The Serological and Morphological Relationships of Plant 



Viruses . Study and identify plant viruses using their morphological 

 and serological relationships. 

 PI. Path. 756 



111. Plant-Virus Purification with Emphasis on the Curly-Top Virus 

 and its Relation to Horseradish Brittle Root and Degeneration . 

 Purify and characterize curly-top virus. Learn cause of horse- 

 radish brittle root and degeneration. Develop disease control 

 measures when causal agent of diseases is proven and characterized. 

 PI. Path., Hort. 68-371 Coop. ARS 



