Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: September 9, 2003
Publication Date: June 1, 2004
Citation: Gottwald, T.R. 2004. An overview of the epidemiology of citrus tristeza virus. Phytopathology. 94:S131. Technical Abstract: Epidemics of mild and decline-inducing isolates of Citrus tristeza virus (CTV) were assessed in Florida, Costa Rica, The Dominican Republic, Puerto Rico, and Spain, where the predominant vector for the pathosystem was either <i>Aphis gossypii</i> or <i>Toxoptera citricida</i>. The vector population composition affected the spatial pattern and rate of CTV increase. In the <i>A. gossypii</i> CTV pathosystem, virus incidence reached an asymptote after 8-14 years and was spread through a combination of random transmission originating from inoculum outside the plot and local transmission from within-plot sources operating over short distances. In contrast, virus incidence of the <i>T. citricida</i> CTV pathosystem required only 2-4 years to reach an asymptote, and spread was accounted for by short-range transmission within a local area of influence. Long distance spread of CTV was documented by <i>A. gossypii</i> over many kilometers, and spread by <i>T. citricida</i> was recorded up to 4.0 km. Virus increase was most rapid in orange, slower in grapefruit, and even slower in lemon plantings, although there was little difference in the resulting spatial pattern. Vector control had little effect on CTV increase and spread. Insecticides suppressed aphid infestation of citrus, but aphid feeding occurred on insecticide-treated trees prior to aphid death, and was sufficient for CTV acquisition and transmission.