Behavior of five valencia sweet oranges selection under high inoculum pressure of citrus variegated chlorosis (CVC).

Citrus variegated chlorosis (CVC), caused by the Xylella fastidiosa pv. pauca is one of the most important diseases that affect the Brazilian citrus industry. Sweet oranges are the most susceptible to the bacteria. The aim of the current work was to evaluated the disease evolution on five selection of the 'Valencia' and 'Natal' and 'D. João' sweet orange cultivars grafted on 'Swingle' citrumelo and 'Sunki' mandarin rootstoks in field conditions of high inoculum pressure, in Bebedouro, SP, Brazil. The experimental layout was a complete randomized block design, with 4 replicates and 7 treatments with two trees per plot. The treees were evaluated by visual assessments performed once a year using a 4-note scale. With the number of trees inspected and their grades the disease index was calculated for the two years. Results were submitted to analysis of variance using the Fischer's test and the means compared by the Tukey test (P