Virus Research at The James Hutton Institute

Research into the viruses of soft fruit crop plants has been done at The James Hutton Institute since the early 1950s, leading to the identification of the causal agents of many raspberry diseases and to the development of testing procedures and specific diagnostics for numerous raspberry viruses. This work is continuing, incorporating modern technologies to characterise at the molecular level viruses already known to affect Rubus plants, as well as newly emerging viruses that become apparent as a result of alterations in cultivation practices and environmental conditions. The results from this work are used by James Hutton Institute entomologists and soft fruit geneticists to develop new fruit varieties that are resistant to viruses and their insect vectors.

You may be interested to look at our database of soft fruit viruses which contains information on over 60 soft fruit viruses reported to occur in raspberry, blackcurrant, strawberry and blueberry.

Root Rot Research at The James Hutton Institute

Raspberry root rot is a serious soil-borne disease caused by the fungal infection of raspberry roots, crowns and the bases of young and old canes by Phytophthora.

Several Phytophthora species are known to infect red raspberry, but the most prevalent pathogen in serious disease outbreaks is Phytophthora fragariae var rubi, which is very closely related to the fungus causing strawberry red core.

Raspberry root rot only became apparent as a problem for Scottish raspberry producers in the mid-1980's, but with its rapid spread and severity across Europe work began at The James Hutton Institute on this major disease problem facing the soft fruit industry. Root rot is now the most destructive disease of raspberries in the UK. All parts of the plant below or at ground level can be infected and affected canes die in the first year of growth or their buds fail to emerge at the start of the second growing season. Alternatively, emerged laterals wilt and die at any time from emergence until late in fruiting.

Pathogen Testing at The James Hutton Institute

The James Hutton Institute is the sole UK establishment with the expertise and facilities to produce pathogen tested (PT) foundation stocks of Rubus, Ribes and Fragaria. The James Hutton Institute is an international centre for the supply of such PT germplasm for scientific and commercial use worldwide. Because of its reputation and integrity in this capacity, the James Hutton Institute has special relations with several countries whereby their strict quarantine regulations are relaxed for material originating as PT stock from The James Hutton Institute. In addition to production of PT stocks, we can also offer a full range of pathogen testing services for Rubus, Ribes and Fragaria. These range from testing for a single pathogen to testing for the full range of pests and diseases affecting these stocks. Please contact us for more information.

Our prime role is to provide the industry with high health soft fruit plants for propagation. Pathology testing is applied to provide mother plants that are then maintained in 'state of the art' glasshouses. Our pathology testing uses the best tests available, many of which were first devised at The James Hutton Institute, to screen for a variety of fungal, bacterial and viral diseases and nematode pests of Rubus, Ribes and Fragaria. The mother plants provide planting material for propagation into the UK soft fruit industry.

Secondary roles include (a) providing pathogen tested research material to international organisations, (b) pathogen testing of commercial soft fruit samples.

General Introduction to raspberry pests and diseases

Plantations can crop productively for more than 15 years, but this is only possible if the planting stocks, soils and general environment are free from viral, bacterial and fungal pathogens and certain pests. The most common reason for replanting is degeneration caused by infection with pests and diseases, particularly virus pathogens that cannot be eliminated once plants become infected and which can cause very severe symptoms in mixed infections. Hence, in considering the factors that dictate whether a plantation will be long-lived and productive, it is important to plant healthy propagation material from a recognised certification scheme and to manage pests (particularly those that transmit virus pathogens) and diseases throughout the life of the plantation.

Raspberries and their hybrids are subjected to attack by a wide range of pests and diseases and substantial losses in yield and fruit quality occur throughout Europe. Currently, many of the pests and diseases can be adequately controlled by use of chemicals applied to the crop. However, disease control strategists face the withdrawal of approved products, a restriction in the number or times of application of the control products and fungicide resistance in some pathogens.

Phytophthora root rot and botrytis grey mould are by far the most serious of the fungal diseases in Europe, resulting in extensive losses and significant levels of chemical application. Other fungal pathogens of concern include those causing cane and foliar diseases. Virus infections in Rubus crops are particularly important because mixed infections with different viruses can lead to very damaging symptoms and disease. Viruses are spread within plantations by pollen transfer, nematodes and aphids, but at present aphid-transmitted viruses are probably causing the most important virus diseases in the UK. There are effective sources of resistance to some aphids in certain cvs, although resistance-breaking aphid biotypes have developed. Virus spread can be limited by insecticide use to kill aphid vectors, but in the longer term natural resistance to aphids or virus are more promising routes to follow. Of the raspberry pests, aphids (because of the viruses they transmit) and raspberry beetle (because of the fruit quality problems they induce) are probably the most important.

The above problems are increasing pressure on plant breeders and pathologists to identify and incorporate new sources of host resistance into commercially acceptable genotypes.

Pests and Diseases

Pests and diseases remain a threat to production and cause serious economic losses to growers. There are a number of reasons for continuing vigilance with pests and pathogens including: imminent changes in EU-wide pesticide harmonisation plans will mean the withdrawal of many pesticides, and control of many pests and diseases will become more difficult in the short- to medium-term; the risk of hitherto unrecognised pests and diseases in Scotland increasing in importance due to protected cropping systems and/or climate change; changes of varieties which can result in a change in susceptibility to pests and diseases.

Thus, in addition to the long-term development of new germplasm with durable resistance genes, particularly against aphids, viruses and Phytophthora spp. There is a need to identify appropriate integrated pest and disease management (IPDM) strategies for the short- to medium-term. For example, we are developing methods for non-pesticidal control of raspberry beetle and raspberry cane midge using semiochemical approaches and attractant-enhanced traps.

Provision of Nuclear Stock Planting Material 

The provision of disease-free nuclear stock of soft fruit germplasm represents a statutory requirement, because propagation of high-health planting material is crucial to the sustainability of commercial production throughout the UK. The Institute is the sole UK establishment with the expertise and facilities to produce pathogen tested (PT) foundation stocks of Rubus, Ribes and Fragaria, and we are an international centre for the supply of such PT germplasm for scientific and commercial use worldwide.

Our pathogen detection protocols use the best tests available, many of which were first devised at the Institute, to screen for a variety of fungal, bacterial and viral diseases and nematode pests of Rubus, Ribes and Fragaria. We will continue to devise improvements in the methodology for maintaining nuclear stock, particularly the increased use of PCR-based pathogen detection protocols, which will raise the overall health status of the UK fruit industry, thereby assisting its sustainability.