Project Number: 5358-12220-003-01
Project Type: Specific Cooperative Agreement

Start Date: Jul 25, 2006
End Date: Sep 30, 2008

Objective:
Determine under controlled conditions if exposure of lilac and quaking aspen to a freezing event increases the severity of bacterial blight. Determine if reduced severity of bacterial blight on aspen and lilac grown under plastic shelters is associated with reduced leaf wetness or fewer frost events.

Approach:
The influence of frost events on infection of lilac and quaking aspen leaves and shoots will be studied in repeated laboratory assays. Plants coming out of dormancy will be inoculated at bud break and at leaf expansion by spraying a suspension of a rifampicin-marked strain of Pss. After incubation in a mist chamber a subset of plants will be exposed to-2 to -5 degrees Celcius. Incidence and severity of leaf spot and shoot dieback will be compared. Two field trials, one on lilac and the second on aspen, will be conducted at the Botany and Plant Pathology field laboratory of Oregon State University near Corvallis. An experiment on the influences of wetness and frosts on bacterial blight will be conducted on an established block of lilac 'Ellen Willmott'. A similar field experiment will be on aspen maintained in containers at the field site. Documents SCA with OSU. Formerly 5358-12220-002-04S (8/07).