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Novel strategies for optimising powdery mildew management on outdoor cucurbits and protected herbs - PS2125

Description
1. Background to the project and overall purpose:

Powdery mildew diseases affect the yield and quality of a wide range of edible and non-edible horticultural crops both in field and protected production (e.g. cucurbits, herbs, soft fruit, brassicas, carrots, cut flowers and ornamentals). Despite commitment by UK growers to minimising pesticide use, many are reliant on the use of a very small number of approved conventional fungicides on crops at risk from powdery mildew, in order to achieve marketable quality and yield. For powdery mildew diseases, several potential alternatives to conventional fungicides have been identified and in some cases are commercially available, but are not fully exploited in the UK. There is good evidence of powdery mildew control by inorganic salts (bicarbonates, silicates, phosphates and chlorides) with 11 commercial products approved as ‘biopesticides’ in the USA. In the UK potassium bicarbonate has a commodity substance approval for control of powdery mildew but use to date has been limited. Other potential products include Milsana (extract of giant knotweed) approved in Germany as a `plant strengthener`, with research demonstrating that this product can control powdery mildew, reportedly stimulating plant defence responses. This product is not currently marketed in the UK. SB Plant invigorator is a product marketed primarily for its insecticidal properties but with a physical mode of action that reportedly prevents the spread of powdery mildew. A range of biological control agents are used for powdery mildew control on horticultural crops in the USA, e.g. Serenade (Bacillus subtilis) which is currently undergoing registration as a biofungicide in the UK.
The overall purpose of the project is to reduce grower reliance on conventional fungicides available for powdery mildew control. The research effort will be targeted at high disease risk crops where there are limited modes of action and intractable disease problems, and potential residue implications. The proposed work is in line with the Product Availability Action Plan of the Defra Strategy for the Sustainable Use of Plant Protection Products, by potentially increasing product choice for control of diseases on minor crops which are currently served by few approved fungicides.

2. Objectives of the proposed research:

The specific objectives are:
1. Identify the efficacy of inorganic salts, biological control agents (BCAs) and other products against powdery mildew via high through-put screens, using squash/pumpkin and parsley as model crop systems.
2. Validate the efficacy of compounds and products on outdoor cucurbits and protected herbs under semi-commercial conditions, and develop a programmed approach to the integration of products into commercial practice.
3. Evaluate selected novel products for their effects on invertebrate BCAs in protected parsley, using laboratory bioassays and crop experiments.
4. Develop appropriate linkages with key industry players in order to identify potential pathways for approval of effective products and future uptake by UK growers.

3. Scientific approaches and work plan:

Selected products (with emphasis on inorganic salts) will be evaluated in model systems on two crops highly susceptible to powdery mildew, representative of different sectors and for which there may be residue issues (outdoor cucurbits and protected parsley). In year 1, inoculated glasshouse experiments will be done to determine product efficacy. In year 2, integrated strategies relevant to the selected crops will be tested in semi-commercial and commercial situations, while also testing compatibility with invertebrate BCAs.
4. Benefits expected to result from the research:

Since the project will focus partially on available products, uptake by the industry could be immediate but with scope for further commercial development if unregistered products showed potential. For example, promising results using salts for powdery mildew control could provide the basis for approval via the commodity substance or biopesticides route. Through objective 4, involvement from product manufacturers as consortium members will enable potential routes for progressing product approvals to be identified. A strong element of technology transfer is planned with presentations to grower groups and trade press articles. Findings for the selected crops in the project are expected to have wider applicability for the horticultural industry.
Objective
The technical and scientific aims of the research are:

1. Identify the efficacy of inorganic salts, biological control agents (BCAs) and other products against powdery mildew via high through-put screens, using squash/pumpkin and parsley as model crop systems (months 1-15).

2. Validate the efficacy of compounds and products on outdoor cucurbits and protected herbs under semi-commercial conditions, and develop a programmed approach to the integration of products into commercial practice (months 15-23).

3. Evaluate selected novel products for their effects on invertebrate biological control agents (BCAs) in protected parsley, using laboratory bioassays and crop experiments (months 10-23).

4. Develop appropriate linkages with key industry players in order to identify potential pathways for approval of effective products and future uptake by UK growers (months 1-24).
Project Documents
• FRP - Final Report : PS2125 final report   (498k)
Time-Scale and Cost
From: 2009

To: 2011

Cost: £218,560
Contractor / Funded Organisations
ADAS UK Ltd.
Keywords
Application              
Biological Control              
Biopesticide              
Chemicals              
Crop Diseases              
Disease Control              
Fungicide use              
Pesticide use              
Pesticides              
Plant diseases              
Plant health              
Plants and Animals              
Vegetables              
Fields of Study
Pesticide Safety