Apium virus Y

"Apium virus Y" (ApVY) is a plant pathogenic 
virus in the genus "Potyvirus" and the virus family "Potyviridae".
Apium virus Y is a recently described member of the potyvirus family. It was first found in Australia in 2002 in poison hemlock ("Conium maculatum": an immigrant weed in Australia). A survey of native and weed species in the family Apiaceae found ApVY to be widespread in Australia. In addition, this survey and others found two other potyviruses. One was a well-known potyvirus infecting the Apiaceae, "Celery mosaic virus" (CeMV). CeMV has been found in celery ("Apium graveolens") crops worldwide, including Australia, New Zealand and the US. The third potyvirus found in these surveys was another previously unknown potyvirus, Carrot virus Y (CarVY).
Geographic distribution.
Since its sequence was first deposited in GenBank, ApVY has been found in Florida, Washington state and California in the United States and in New Zealand. In New Zealand, it was found in celery in a mixed infection with CeMV.
In Washington state two different strains of ApVY were found, one in domestic celery crops and other in the weed poison hemlock. The one in celery was 98% identical to the Australian nucleotide sequences. The one found in naturally infected poison hemlock was only 91% identical to the sequences from Australia. The later turned out to be 98% identical to the North American isolates found in Florida and California. In turn, the Florida isolate was 90-91% identical to the Australian isolates.
A third strain of this virus has been known in Germany since the early 1990s. Sequences of this virus isolated from parsley ("Petroselinum crispum") were 94% identical to the Australian isolate from parsley. (H.-J Vetten, personal communication)
Host range and symptoms.
In addition to cultivated celery and parsley and the weed poison hemlock, ApVY infections have been identified in sea celery ("Apium prostratum"), cilantro ("Coriandrum sativum"), and bishop’s weed ("Ammi majus"). In Germany it has recently been found naturally infecting celeriac or celery root. All are members of the plant family "Apiaceae".
Symptoms reported included mosaic, vein clearing or banding, necrotic/chlorotic line patterns and stunting. Some samples of parsley, celery and poison hemlock, that gave positive results in tests, however, were asymptomatic.
In host range studies, the virus causes local lesions on "Chenopodium quinoa" and "C. amaraticolor" ("Amaranthaceae").