Symptoms and Signs
Disease symptoms caused by Apium virus Y are variable and depend on the celery cultivar. In general, older leaves show yellow or brown line patterns, yellow blotches, brown lesions, and in some cases have distorted and twisted leaflets. Younger leaves may show a faint mosaic or mottling. Celery petioles could exhibit dark brown, sunken, elongated lesions. However, for some cultivars, the celery plants having symptomatic foliage will not have any petiole symptoms. Overall plant growth does not appear to be affected.
Comments on the Disease
Apium virus Y has only recently been reported in California and is thus far documented only in the Central Coast region. In addition to celery, this virus has been found in the field on cilantro, parsley, and the weed poison hemlock (Conium maculatum). This virus is vectored by aphids, and seed-borne transmission has not been reported.
Management
Cultural Control
Elimination of weed hosts like poison hemlock appears to be important, as most Apium virus Y cases occur where this weed is widely distributed.
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.