Late blight, caused by Septoria apiicola Speg., is the most important disease affecting celery in Quebec. Biological control was investigated as an alternative to conventional chemical control of late blight. Two hundred and four bacterial isolates were collected from celery leaves, and muck and mineral soils of celery fields in south-western Quebec. Two experiments were conducted to screen the bacteria for antagonism toward Septoria apiicola: one on agar to test for inhibition of pycnidial formation, and the other on leaf disks to test for inhibition of germination of conidia. From these two experiments, 18 isolates were selected that prevented pycnidial formation in an inhibition zone $ ge$1.0 cm wide and reduced germination to below 30% of the control. These isolates were re-evaluated for inhibition of germination on leaf disks. A bacterial suspension (10$ sp7$ cells/ml) was incubated on leaf disks for 24 hours before a suspension of S. apiicola conidia (150,000 spores/ml) was applied, and the disks were incubated for 25 hours. Four isolates reduced germination to $ le$19% of the control. These isolates were tested on plants in a greenhouse. None of the isolates was able to reduce the number of late blight lesions compared to the control.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.23914 |
| Date | January 1995 |
| Creators | Lovering, Nancy |
| Contributors | Kushalappa, A. C. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Plant Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001488793, proquestno: MM12229, Theses scanned by UMI/ProQuest. |
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