Symptoms and Signs
Disease symptoms caused by Celery mosaic virus include yellowing of foliage, mosaic and/or mottling patterns on leaves, vein clearing, and curled, crinkled, or otherwise distorted foliage. On older leaves necrotic leaf spots may develop. Plants are sometimes stunted. Outer petioles grow horizontally, giving the plant a flattened appearance. Certain strains of the virus may cause more severe symptoms than other strains.
Comments on the Disease
Celery mosaic is the most common viral disease of celery. The virus is not reported to be seedborne; it is vectored by aphids. Celery is the primary host of this disease.
Management
Cultural Control
For celery mosaic, a host-free period of at least 2 to 3 months (in which celery is not being grown in the area) greatly reduces the incidence of celery mosaic. Eliminate weed hosts like wild celery and wild parsnip, especially during the celery-free period. Although resistance has been reported in other areas, it does not pertain to commercial varieties used in California.
Organically Acceptable Methods
Cultural controls are acceptable for use on organically grown produce.
Treatment Decisions
Chemicals are not effective against plant viruses. Insecticides for controlling the vector are not effective in preventing virus infections.