Incidence and epidemiology of Citrus tristeza virus in the Valencian Community of Spain

• Published in: Virus research Vol. 71; no. 1; pp. 85 - 95
• Main Authors: Cambra, Mariano, Gorris, Marı́a Teresa, Marroquı́n, Carlos, Román, Martha P., Olmos, Antonio, Martı́nez, M.Carmen, de Mendoza, Alfonso Hermoso, López, Antonio, Navarro, Luis
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2000
• Subjects: Animals; Aphid vectors; Aphididae; Aphids - virology; Aphis gossypii; Aphis spiraecola; Citrus; Citrus - virology; Citrus tristeza virus; Closterovirus - isolation & purification; Detection; Epidemiology; Insect Vectors - virology; Plant Diseases - virology; Spain; Spatial and temporal spread; Toxoptera aurantii; Trees - virology; Spain; Citrus tristeza virus; Spatial and temporal spread; Detection; Aphid vectors; Epidemiology
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/S0168-1702(00)00190-8

The first outbreak of citrus tristeza disease in Spain caused by
Citrus tristeza virus (CTV) was recorded in 1957 in the Valencian Community (VC). In total
c. 40 million trees, mainly of sweet orange and mandarin grafted on sour orange rootstocks, declined due to CTV. Large-scale surveys in different municipalities of the VC indicated that the disease spread very fast. Incidence increased from 11% in 1989 to 53% in 1998.
Toxoptera aurantii and
Aphis spiraecola (inefficient aphid vectors of CTV) predominated before 1985–87. Since then the relatively efficient vector
Aphis gossypii has become dominant and induced an epidemic that has been modelled. The large number of
A.gossypii that visited each clementine tree (estimated to exceed 97
 000 per year) explained the difference between the temporal pattern of spread of CTV in clementine which followed the Gompertz model and that in sweet orange (logistic model). The susceptibility of the different citrus species to CTV infection by aphids seems to depend on the number of young, succulent shoots produced. The epidemiological data allowed specific recommendations to be made to growers in order to facilitate a change to a modern citrus industry based on the use of selected varieties grafted on tristeza-tolerant rootstocks produced within a certification scheme. This has been done already in almost 90% of the VC citrus-growing area. The tristeza problem has been solved unless more aggressive isolates are introduced and become prevalent.