|Bergamin filho, A.|
Submitted to: Popular Publication
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/10/2003
Publication Date: 4/1/2004
Citation: Laranjeira, F.F., Bergamin-Filho, A., Amorim, L., Gottwald, T.R. 2004. Fitopatologia Brasileira. 29:056-065. Interpretive Summary: Citrus Variegated Chlorosis is considered a very serious and production limiting disease in Brazil with potential to be introduced into the US. We have several sharpshooter insect species that can vector this bacterial disease of citrus, and it introduction into the US could potentially be quite devastating. The distribution of the disease was studied in the state of Sao Paulo Brazil in the Northwest, Central and southern citrus growing regions. Results of the study of the disease distribution pointed to the likely interaction of two different vector species. The first insect species most likely brings the disease from surrounding areas to the edge of the citrus planting. A second insect species is apparently responsible for moving the disease within the planting. These findings are important to understand how various insects move the disease organism and give clues as to how to control the disease by vector control.
Technical Abstract: CVC is considered the most important disease of the Brazilian citrus industry but many aspects of its epidemiology are still unknown. This work aimed to characterize the spatial pattern of CVC affected trees in three regions (Northwest, Center and South) of Sao Paulo state, Brazil. Three orchards of Pera sweet orange (Citrus sinensis) grafted on Rangpur lime (Citrus limonia) were evaluated twice a month by visual assessments from July 1998 to December 2000. For each evaluation all plants were inspected and assigned as diseased or healthy and cumulative maps were produced. The following analyses were performed: ordinary runs, isopath areas, Taylor law, dispersion index and foci structure and dynamics analysis. Ordinary runs indicated a trend to randomness. Isopath areas analysis showed few compact foci and a trend to uniform incidence in all areas. The other analysis showed few if any differences between regions and results that could classify CVC pattern as slightly aggregated.