|Garnsey, S. - ARS RETIRED|
|Gumpf, D. - UNIV OF CALIFORNIA|
|Brlansky, R. - UNIV OF FLORIDA|
Submitted to: Conference of International Organization of Citrus Virologists
Publication Type: Abstract Only
Publication Acceptance Date: July 4, 2005
Publication Date: N/A
Technical Abstract: Symptom expression of 267 different isolates of CTV originating from 30 countries was determined by graft-inoculation of Mexican lime, sour orange, Madam vinous sweet orange and Duncan grapefruit seedlings, and a grafted combination of sweet orange on sour orange rootstock. Testing was conducted over 16 yrs in a USDA quarantine facility at Beltsville, MD. Readings for foliar symptoms and stem pitting in each test were made for 12 months and compared to standard isolates. Plants which remained symptomless were tested by ELISA to verify infection. These standardized tests in a single facility confirmed that the wide range of symptom severity observed can be directly attributed to differences among CTV isolates. The patterns of symptom expression observed in the five indicators indicated that seedling yellows, the decline syndrome in sweet orange grafted on sour orange, stem pitting in sweet orange, and stem pitting in grapefruit are independent expressions of CTV pathogenicity and may occur in various combinations. Associations between symptom expression and reactions to selective serological or molecular markers are also reported.