Introduction
The Gladiolus scab is caused by the bacterium Pseudomonas
syringae.
Symptoms
Lesions on corms are pale yellow, water-soaked
circular spots, deepening to black or nearly black. These
eventually become sunken with raised brittle margins that
are scab-like and exude a gummy amber substance.
Figure 1: Symptoms
of gladiolus Scab. (provided by Cornell
University) |
Figure 2: Foliar symptoms. (provided by
Cornell University) |
|
Disease
Cycle
Bacteria over-winter on corms. Shortly after planting,
tiny reddish raised specks appear on leaves, mostly near the base.
These enlarge to dark sunken spots which grow together into large
areas, causing either firm or soft rots of the neck or the basal parts.
Injury to the corm by bulb mites, grubs, or wireworms may increase
in the incidence of Gladiolus scab.
Management Strategies
Examine corms before planting, and plant only quality corms
that are free of disease or insect injury. Commercially prepared pre-planting
corm treatments may be used. Corms are best treated without removing
the husks. Dry corms well before storage and over-winter in a cool
(40-45°F) well-ventilated place.
Created, KLS, 1/01, Updated 1/05
This publication may contain pesticide recommendations. Changes in pesticide
regulations occur constantly, some materials mentioned may no longer
be available, and some uses may no longer be legal. All pesticides distributed,
sold, and/or applied in New York State must be registered with the New
York State Department of Environmental Conservation (DEC). Questions
concerning the legality and/or registration status for pesticide use
in New York State should be directed to the appropriate Cornell Cooperative
Extension Specialist or your regional DEC office. READ THE
LABEL BEFORE APPLYING ANY PESTICIDE. __________________________________________________________________________________
The Plant Disease Diagnostic Clinic
at Cornell University is located at 334 Plant Science Building,
Ithaca, NY, 14853. Phone: 607-255-7850, Fax: 607-255-4471,
Email: kls13@cornell.edu
or slj2@cornell.edu |
