An epidemic of celery mosaic potyvirus in celeriac (Apium graveolens var. rapaceum) in the Netherlands

Abstract

An annually recurring virus epidemic has caused severe damage and sometimes total yield loss in crops of celeriac in the south-west of the Netherlands for several years since 1969. Celery latent virus, cucumber mosaic cucumovirus and tobacco rattle tobravirus were isolated from diseased plants, but a potyvirus was the most prevalent virus present. It did not cause local lesions in Chenopodium amaranticolor or C. quinoa and did not infect other non-Umbelliferae.The virus was identified as celery mosaic potyvirus and confirmed to be the causal agent.Field surveys from 1971 to 1977 showed a rapid increase of disease incidence in consecutive years, soon leading to near-abandonment of the crop in the original centre of cultivation and its northward translocation, gradually followed by the disease. Incidence in fields often increased from zero by the end of July, when symptoms first appeared, to 100% early during September. In 1976 final incidence was 75 to 100% in 41~ of the fields inspected. Temporary protection with aphid-proof cages showed that first infection occurred about three weeks before symptoms appear and not before the beginning of July, and that the virus may still spread after late September.When testing samples from other umbelliferous crops and wild species near infested crops, several viruses were detected but not celery mosaic virus. The virus may be introduced from yet unknown distant sources, as also suggested by the pattern of spread in crops of celeriac.Celeriac cultivars differ considerably in resistance to the virus, but resistant cultivars generally are of poorer quality for consumption and processing than the original highly sensitive cultivar. In recent years cultivation has recovered considerably with the advent of new cultivars.

Survey and biological differentiation of viruses of wild and cultivated umbelliferae in the Netherlands

“…TRV was found once in celeriac with yellow (ring)spotting and leaf malformation, and these symptoms could be reproduced in celeriac by sap inoculation (Bos et al, 1989). Similar symptoms have been described by Wolf and Schmelzer (1973) for carrot with TRV.…”

“…In the south-west of the country it has caused a severe epidemic in celeriac in the 1970s (Bos, 1973;Bos et al, 1989). It has never been found in carrot or wild Umbelliferae, reported to be natural hosts in other countries (Table 3), and searches for natural sources of infection to explain the annual recurrence of the epidemic have so far been in vain.…”

“…Soon thereafter young leaves remain short with narrowing and curling of leaflets (Fig 6, right) showing a typical vein-banding mosaic. Affected plants remain small especially when infected early, and yield reduction may be considerable to almost total (Bos et al, 1989). Symptoms of CeMV can easily be distinghuished from those of CMV but may be confused with those of PMV (see under Parsnip mosaic virus and Fig.…”

“…In nature the easily sap-transmissible potyvirus has only been found in Umbelliferae. The Dutch isolates from celery and celeriac were identified by their host range and symptoms, especially in A. majus, celery, celeriac and carrot (Table 4), as well as by their particle morphology and size and particle decoration with antiserum to CeMV (Bos et al, 1989). The literature differs as to the experimental host range of the virus.…”

“…CeMV has caused much concern in celeriac in the south-west of the country, partial resistance in newly developed cultivars being an acceptable remedy (Bos et al, 1989). Searches for sources of infection of CeMV and of PYFV among cultivated and wild Umbelliferae to find possible ways of preventing crop infection, led to the detection of a number of viruses other than CeMV.…”