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Biofumigant crops as replacements for methyl bromide soil sterilisation in strawberry production - HL0177LSF

To develop scientifically based techniques that will underpin environmentally acceptable alternatives to chemical disinfestation and sustain UK strawberry production as part of an integrated package to overcome Verticillium dahliae.

UK strawberry production has an ex-farm value of £118M and is expanding rapidly to meet rising consumer demand. Production is 95% soil-based and a lack of virgin land is a problem for both conventional and organic growers. The most important soil borne disease is caused by the fungus V. dahliae, which is capable of causing significant crop and economic losses. Effective control of V. dahliae can only be achieved by soil sterilisation resulting in the widespread use of methyl bromide to sterilise soil used for strawberry production. Despite thorough investigation (Horticulture LINK project 215) a suitable sustainable soil-less substrate for growing strawberries has yet to be identified.

Methyl bromide will be banned from use in 2008 and this poses a huge threat to productivity. For example, losses from vascular wilt caused by Verticillium dahliae in strawberries may be up to 75% in infected, untreated soils. Other chemical controls, such as chloropicrin and dazomet, are less effective and it is uncertain how much longer their use will be permitted or acceptable to the consumer. Steam sterilisation is being considered elsewhere, but is currently uneconomic and energy inefficient for most soil types. In organic production systems soil sterilisation by chemicals or steam is not an option. Development of strawberry varieties with increased disease resistance could provide a long-term solution, but resistance tends to be pathogen and cultivar specific. ‘Elsanta’, a disease prone variety, is currently favoured by supermarkets for both conventional and organic sales and this is unlikely to change in the medium term. What is needed in the short to medium term is an alternative to chemical soil sterilisation that is reliable, has a high level of efficacy, is.environmentally benign, is acceptable to the consumer and can be incorporated into standard farming practice, including organic production. Biofumigation, based on the process of using plant-derived volatile chemicals to supress soil borne diseases, has such potential. There has been little scientific assessment of its use in horticultural crops in the UK. In the USA, Brassicaceae biofumigant crops are currently being utilised as a green manure on over 16,000 ha of land2, largely for potato crops. Similarly, research at ISCI in Italy has led to production of brassica cultivars, promoted by the company Cerealtoscana, that are now available in the UK via Plant Solutions Limited. Data on strawberry and Verticillium wilt remain extremely limited, particularly in northern European climates. One study in Italy has identified that brassica biofumigants were effective in terms of increasing strawberry yield. However, no commercial strawberry crops are currently being grown following biofumigation (R. Harnden, KG Fruits Ltd pers. comm.) A recent industry commissioned report strongly recommends that R&D on biofumigation in the UK should be carried out.
1. Screen crop species for substantive biofumigant effect against V. dahliae.

2. Define the link between phyto-chemicals, soil microbiology and pathogen viability.

3. Identify agronomic practices that optimise use of biofumigant crops in strawberry rotations.

4. Develop strategies for optimising use of biofumigant crops
Time-Scale and Cost
From: 2006

To: 2010

Cost: £348,658
Contractor / Funded Organisations
Natural Resources Institute, Horticultural Development Council, KG Growers Ltd, The Hunter Hall Partnership, Henry Doubleday Research Association, Plant Solutions Ltd, Berryworld Ltd, East Malling Research, Hugh Lowe Farms Ltd, East Malling Ltd, Marks and Spencer plc, EM Trust for Horticultural Research, Farm Advisory Services Team
Climate Change              
Protected Cropping              
Sustainable Farming and Food              
Sustainable Production              
Fields of Study
Resource Efficient and Resilient Food Chain