SUMMARY Pear scions cv. ‘Abate Fetel ’ on B29：（摘要梨子嗣的简历。）.pdfVIP

Journal of Plant Pathology (2002), 84 (3), 157-160 Edizioni ETS Pisa, 2002 157 SHORT COMMUNICATION ONE YEAR SURVIVAL OF ERWINIA AMYLOVORA IN SYMPTOMLESS PEAR SCIONS F. Traversa and U. Mazzucchi Dipartimento di Scienze e Tecnologie Agroambientali, Università degli Studi di Bologna, Via Filippo Re 8, I-40126 Bologna, Italy SUMMARY was found in association with buds on apple rootstocks (Calzolari et al., 1982), but this material was not an ef- Pear scions cv. ‘Abate Fetel’ on B29 rootstock were fective source of infection in the orchards where it was raised individually in pots from dormant buds. In au- planted. A fire blight focus was, on the other hand, tumn 1999, the main stems were divided into 5 groups found in Emilia Romagna in illegally imported and inoculated at 10 day intervals starting from 21 hawthorns (Curto, 1992). No information is as yet avail- September with a virulent RifR mutant of Erwinia able on how symptomless nursery material used for amylovora . For the inoculation, 30,000 cells of E. planting in areas free from fire blight may act as a pri- amylovora were deposited on a transverse cut 10 cm mary source of inoculum, or on the timescale involved. from the tip. After ensuring establishment of the A likely hypothesis is that the bacteria may survive en- pathogen, the five groups of plants were placed in the dophytically in symptomless host plants for long peri- open and inspected weekly for th