During the 2002 growing season a research was conducted in order to establish the causal agents responsible for "soft rot" in stems and tubers of calla (
Zantedeschia
spp.) in greenhouse productions in Southern Chile. In order to compare with local bacterial isolates, "soft rot" was induced in potato (
Solanum tuberosum
L.) tubers from commercial productions near the city of Valdivia. To establish differences in virulence, potato isolates were inoculated on calla tissues and viceversa. 33 isolates were determined to belong to the genus
Erwinia
(
carotovora group) (
E.c.) accordingly to the following characteristics: Gram (-), oxidase (-), potato rot. Complementary and more specific tests included, sensitivity to erythromycin, utilization of palatinose, reducing substances from sucrose, acid production from a-methyl glucoside and growth at 37°C. Finally, it was possible to identify two isolates of
E.c. subsp.
atroseptica and 21
E.c. subsps.
carotovora isolatedfrom calla plants tubers. There was no evidence of the phytopathogenic species
E. chrysanthemi among the isolates studied, an indication that this bacterial pathogens is absent in Chile. This is the first report indicating that isolates of
Erwinia carotovora subsp.
atroseptica
are affecting a new crop in Chile, such as calla. The cross inoculations performed demonstrated that virulence is more aggressive with isolates originated obtained from calla tissues. Chances that the isolates obtained from calla came from abroad are very high, and may interfere with local crops such as potato.
