Grant Information

CALIFORNIA CITRUS TRISTEZA VIRUS SURVEY

Sponsoring Institution Agricultural Research Service/USDA
Status ACTIVE
Funding Source USDA INHOUSE
Reporting Frequency Annual
Project Director YOKOMI R K
Accession Number 439524
Project Number 2034-22000-014-014R
Dates 2020-10-01 - 2022-06-30
Recipient Organization AGRICULTURAL RESEARCH SERVICE

PARLIER,CA 93648
Keywords epidemiology
genotype
tristeza
Research Effort Applied (40%)
Basic (50%)
Developmental (10%)
Classification Parameters
Knowledge AreaSubject of InvestigationField of SciencePercent
212 - Pathogens and Nematodes Affecting Plants 910 - Grapefruit 1160 - Pathology 34%
212 - Pathogens and Nematodes Affecting Plants 920 - Orange 1170 - Epidemiology 34%
212 - Pathogens and Nematodes Affecting Plants 930 - Lemon 1160 - Pathology 32%
Goals / Objectives
The objective of this research project is to develop a statistically valid estimate of the the incidence of citrus tristeza virus-infected citrus trees in commercial orchards in California and determine the prevalent strains of CTV. This data is needed for an Environmental Assessment and Environmental Impact Statement to support a permit for field release of genetically engineered CTV in California citrus.
Methods (unparsed)

Commercial citrus orchards over 20 acres in size will be selected from 12 major citrus-growing counties and 50 hierarchical subsamples per orchard will be collected and dessicated by silica gel in the field. Samples will be transported to the lab, rehydrated and tested by broad spectrum polyclonal Citrus Tristeza Virus (CTV) and MCA13 antisera. CTV-positive samples will be subjected to strain discriminating primer/probes by RT-qPCR to determine prevalent strain(s) present. RT-PCR and sequencing of some 5' genome regions may be required to confirm genotype. The number of orchards to sample is based on the proportion of citrus acres per county. Sample transport is covered by CDFA movement permit that allows testing for pathogens except huanglongbing (HLB).