Infectivity of Xanthomonas campestris pv. citri and X. campestris pv. citrumelo
In the USA experiments were carried out to investigate the susceptibility of citrus fruit to Xanthomonas campestris pv. citri (EPPO A1 organism) and X. campestris pv. citrumelo (under consideration for EPPO A1 list). The citrus fruit were inoculated with suspensions of strains of the pathogens by a pressurized sprayer keeping the rind of the fruit watersoaked.
The results showed that all citrus fruits were susceptible to X. campestris pv. citri with grapefruit substantially more susceptible than sweet orange or mandarin which was almost completely resistant. Some citrus fruit showed resistance to X. campestris pv. citrumelo.
A strong correlation between the fruit size and the infection and development of symptoms had been observed. Fruits with a diameter of 20-40 mm were infected easily by the pathogens while bigger or smaller fruits were not as susceptible.
Graham, J.H.; Gottwald, T.R.; Riley, T.D.; Bruce, M.A. (1992) Susceptibility of citrus fruit to bacterial spot and citrus canker.
Phytopathology 82, 452-457.