Abstract

Some of the properties of each of the 26 viruses reported in R. crops and spp. throughout the world, their modes of spread and the diseases induced by them are described. Of these, 15 occur in the UK, among which 6 are transmitted by soil-inhabiting vectors, 6 by aphids and 1 through infected pollen. The viruses found most frequently in raspberry in the UK are those transmitted by Longidorus and Xiphinema spp. and by the large raspberry aphid, Amphorophora idaei; the pollen-borne raspberry bushy dwarf virus is the most common virus in loganberry. The economic significance of these viruses is largely determined by the infectibility and sensitivity to infection of cultivars. Generally, the viruses transmitted by nematodes are the most damaging but their distribution is usually localized. In contrast, the aphid-borne viruses are more widespread in crops but their effects are often less obvious and depend both on the sensitivity of cultivars and on whether viruses occur alone or in complex infections with other viruses. Raspberry bushy dwarf and raspberry veinbanding mosaic diseases are caused by complex infections of 2 or more viruses. The methods currently used for detecting R. viruses, and some methods potentially useful, are outlined. Methods being adopted for controlling virus infection in commercial crops in the UK include the production and maintenance of virus-tested planting material, chemical control of nematode vectors, genetically controlled host resistance to aphid vectors and genetically controlled host tolerance, resistance and immunity in relation to individual viruses. The integration of these different approaches should provide an effective strategy for the control of all the viruses of importance in Rubus in the UK.