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Fungal control of diptera. - HH1832SFV

Description
This project will examine and characterise hyphomycete, entomopathogenic fungi as potential biocontrol agents of the cabbage root fly and the onion fly. The larvae of these flies feed on plant roots and reduce the yield of the crop. The cabbage root fly (Delia radicum) is the most serious pest of brassicas. The closely related onion fly, Delia antigua, is a minor pest of onions and leeks. The control of both pests is based on organophosphate and carbamate insecticides, but concerns have been expressed about the continued and widespread use of these compounds. Alternative forms of management, including biological control by entomopathogens, are required.

In previous MAFF-funded work (HHI 822SPC), methods were developed to quantify the effect of entomopathogenic fungi on the survival of third instar larvae of the onion fly, reared on an artificial diet. In this proposal, larvae of the onion fly will be used as a model for laboratory experiments. Published information on fungal biodiversity will be reviewed and the role of biodiversity of entomopathogenic hyphomycetes in relation to virulence and pathogen icity-related characteristics will be appraised. This information will form the basis of a rational strategy for the selection of candidate isolates of fungi for biocontrol programmes. Isolates of fungi with potential activity to Diptera will be obtained from world culture collections. The virulence of candidate isolates of fungi to third instar and neonate larvae of the onion fly will be assessed critically in laboratory bioassays. The effect of temperature on fungus-insect interactions will be modeled in laboratory experiments. Selected isolates of fungi, virulent to larvae of the onion fly, will then be examined for the biocontrol of populations of the cabbage root fly in glasshouse and field experiments.

A reliable, biological method of controlling root feeding Diptera with entomopathogenic fungi would be of considerable benefit to UK growers. This project also addresses MAFF policy objectives to reduce pesticide use, safeguard the quality of produce, and promote sustainable agricultural systems. The findings of the project will be published in refereed journals as popular articles in the trade press as appropriate. Grower-related information will also be made available at HRI subject and open days. The project will be strengthened by the strong associations and previous collaborations between HRI and biocontrol producers through projects involving the development of IPM programmes in protected and field crops.
Objective
The aim of this project is to examine and characterise entomopathogenic fungi as potential biocontrol agents of root feeding Diptera, based on a rational strategy for the selection of candidate isolates. The specific objectives for the proposal are as follows:

1. Fungal biodiversity. Develop rational criteria for the selection of candidate isolates of fungi with potential for the biocontrol of Diptera, and quantify the virulence of candidate isolates to third instar larvae of the onion fly using a standard laboratory bioassay.

2. Bioassay development. Develop a laboratory bioassay to quantify the virulence of entomopathogenic fungi to neonate larvae of the onion fly.

3. Fungus / insect interactions. Quantify the virulence of selected candidate isolates to neonate larvae of the onion fly in laboratory bioassays. Model the effect of temperature on the interaction between entomopathogenic fungi and larvae of the onion fly in laboratory experiments.

4. Interaction with brassicas. Quantify the effect of an isolate of fungus, virulent to larvae of the onion fly, on populations of the cabbage root fly, feeding on brassica plants, in glasshouse and field experiments.
Project Documents
• Final Report : final report   (282k)
Time-Scale and Cost
From: 1999

To: 2003

Cost: £328,410
Contractor / Funded Organisations
Horticulture Research International
Keywords
Biotechnology              
Brassicas              
Farming              
Horticulture              
Onions              
Organic Farming              
Pest Control              
Vegetables              
Fields of Study
Horticulture
Horticulture