During the season of 1980, “gumrny spots” were observed on Armking nectarine’s fruits, at the Padre Hurtado area, in Central Chile. Symptoms consisted in gummy and corky spots, which covered completely the affected fruits. A bacterium, identified as Pseudomonas cichorii, was consistently isolated from diseased fruits. The bacterium was artificially inoculated on healthy nectarine fruits, where field symptoms were reproduced. P. cichorii was thereafter succesfully reisolated from inoculated fruits.