Association of Geotrichum citri-aurantii with citrus groves in Israel

Soil samples from 99 sites in four geographic regions of Israel were examined for the presence of Geotrichum citri-aurantii, the sour-rot pathogen of citrus fruit. The soil at each site was sampled from three locations: the center of, the margin of, and 100 m distant from a citrus grove. Geotrichum spp. were present in all geographic regions, but could be detected in only 183 of 297 locations. Sixty to 80% of the soil samples in the center and margin of the groves contained G. citri-aurantii, whereas only less than 21% of the soil samples outside the citrus grove contained this pathogen. Of the total soil samples, only 10% contained avirulent strains (i.e., G. candidum). Outside the citrus grove, 100 m from the margin, Geotrichum spp. could not be detected at most locations (75-100%). Results indicated a possible association between the sour-rot pathogen and the grove environment in Israel.