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G Plant Disease Vectors 
Calsifi. Insect Vectors of Plant Viruses. (1) Correlate economic 
losses resulting from aster yellows with distribution of strains 
of virus in the State; isolate strains and learn host ranges and 
vector relationships. (2) Maintain cross protection tests with 
strains collected to learn degree of protection occurring in host 
plants and leafhopper vectors. (3) Compare incubation periods and 
retention patterns of virus strains in different species of leaf- 
hoppers following controlled acquisition feeding period of varying 
lengths. (4) Study transmission of viruses by aphids, beetles, and 
leafhoppers. (5) Compare host ranges and symptoms induced by viruses. 
Ent., Parasitol. 657 
Calif. Aphids As Vectors of Field Crop Virus Diseases. Learn and 
clarify the vector-virus-host plant relationships existing among 
the aphid-borne virus diseases of various crop plants. 
Ent., Pl. Path., Parasitol. 1365A 
Calif. Insect Vectors and Their relation to Virus Diseases of 
Deciduous Fruits and Berries in California. To (1) establish 
identity of vectors of the diseases, (2) study life history and 
host plants of vectors, (3) investigate host range of viruses 
when transmitted by insects, and (4) investigate virus vector 
relationships. 
Ent., Parasitol. 1365-B 
Calif. Insect Vectors and Their Relation to Virus Diseases of 
Ornamental Plants. To (1) study insect vectors, properties, host 
range and symptoms of nasturtium viruses in order to distinguish 
them and evaluate their respective incidence and importance and 
(2) determine the insect vector of orchid mosaic virus, properties 
of the virus and its relation to such vectors. 
Ent., Parasitol. 1365-C 
Calif. Insect Transmission of the Orange Tree Quick Decline. To 
investigate (1) identity of vector as determined by transmission 
tests, (2) occurrence and abundance of vector in various citrus- 
growing areas of the state, (3) vector's seasonal life history 
and identity of host plants, and (4) effectiveness of insecticidal 
control of vector in reducing spread of the disease. 
Fnt. 1370 
