Virus diseases of celery in England

Abnormal celery plants (Apium graveolens) with symptoms typical of virus infection were collected from 28 farms in Cambridgeshire, Lancashire, Lincolnshire, and Norfolk; six different diseases were found. The causal viruses from three of these were isolated and partially characterised. Cucumber mosaic virus was quite common, but usually symptomless; it had no effect on the growth of four celery cultivars in field trials. Celery virus 036 was serologically related to western celery mosaic virus, had a host range apparently confined to Umbelliferae, and was very common in the Fens, causing ringspot symptoms in some cultivars and a loss in yield of up to 24%. This disease was much less severe than that caused by an American isolate of western celery mosaic virus in glasshouse comparisons. Celery virus 065 (an unidentified isometric virus, 28–30 nm in diameter) was less common, had a very wide host range, and caused stunting, necrosis, and chlorotic flecking in all cultivars with a loss in yield of up to 45%. Of the remaining three diseases, celery yellow spot was common; the causal agent was transmitted by mechanical inoculation, but very inefficiently, and although yield losses were not determined accurately, they were thought to be insignificant. While plants with symptoms typical of celery yellow net and celery strap leaf diseases were often found, no viruses could be isolated from them, despite repeated attempts.