ARS | Publication request: The Effect of Wind on Dispersal of Splash-Borne Bacteria from Canker-Infested Citrus Trees

Submitted to: Phytopathology
Publication Acceptance Date: June 6, 2004
Publication Date: September 9, 2004
Citation: Bock, C., Parker, P., Gottwald, T.R. 2004. The Effect Of Wind On Dispersal Of Splash-Borne Bacteria From Canker-Infested Citrus Trees. Phytopathology. 94:s9.

Technical Abstract: Dispersal of citrus canker bacteria (Xanthomonas axonopodis pv citri) in wind driven spray and splash was investigated in several experiments. Storm conditions were simulated using electric blowers to generate turbulent wind (c. 40-90 kph) and sprayer nozzles to simulate rain. The rain was fed into the wind stream 1 m upwind from an inoculum source of canker-infected trees. Samples were taken using panels (0.47 m2) placed 1 m downwind at 0, 0.5, 1, 3, 5, 9, 14, 19, 24, 27, 30 and 52 h. Up to 12000 bacteria ml-1 spray sampled were dispersed at 0 h. This number declined over the first 4 h and <400 bacteria ml-1 were subsequently dispersed from 5 to 52 h. Bacteria were collected at all distances sampled (1, 2, 4, 6, 8, 10 and 11 m). Wind speed ranged from 17 to 7 and 5 kph at 1, 6 and 10 m, respectively. The majority of bacteria were recovered at 1 m (#8600 bacteria ml-1), with an exponential decline with distance resulting in #58 bacteria ml-1 beyond 6 m. The results suggest that citrus canker bacteria are dispersed in large numbers in wind driven rain over prolonged periods of time.