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Screening pathogens for the biocontrol of Varroa jacobsoni. - HH0813SHB

Varroa jocobsom is the major pest of honey bees 'I'll is parasitic mite has caused a considerable reduction in the activity and population of UK honeybees. resulting in economic losses to UK farming because of reduced crop pollination. Varroo can be controlled with acaricides. but they contaminate bee products. and pesticide-resistance is developing. Effective alternatives to chemical control are required urgenth.

The objective of this study is to examine and characterise finite pathogens. which have potential as biocontrol agents of Varroo. Entomopathogenic fiingi and the bacterium Bacillus thurmgwrosis (Bt) were identified in a recent MAFF-fimded feasibility study (HH081 I SHB) as having the greatest potential for biocontrol Selected strains of fungi and Bt. with known activity to Aeari. will be evaluated critically in laboraton bioassays against Varroa mites maintained in the laboratory on bee pupae. The bioassay programme will be designed in keeping with a consistent theory of screening. appropriate to the needs of modern biocontrol science Characteristics of mite-active fungi. related to infectivav. Survival and epizootic potential_ will be measured in replicated laborator~ experiments to identify strains that are likely to function within the conditions of the hicc The persistence and spread of potential biocontrol agents within observation hives will be measured in summer and winter. The virulence of selected candidate strains of fungi and Bt to insects and mites from a range of Orders (including beneficial species) will be determined.

The project will be conducted as a partnership beAaeen Horticulture Research International and IACR-Rothatnsted. Scientific findings will be published in refereed journals and as popular articles in the beekeeping press. Information relevant to the beekeeping sector will be made available at IACR/HRI open dad s and through national and regional beekeeping association conventions and meetings The decision of the BBKA executive to base the Institute of Apiculture at IACR-Rothamsted will provide greater opportunities for closer consultation and collaboration and ensure efPectivc technologN transfer An environmentally acceptable approach to the problem of farroo would have considerable economic benefits and be welcomed by beekeepers. It would also meet MATT polio objectives to reduce pesticide use. safeguard the quality of produce, and promote sustainable agricultural systems.
The overall aim of this project is to examine and characterise mite pathogens, which have potential as biocontrol agents of Varroa. The specific objectives for the proposal are as follows:

1. Obtain strains of fungi and Bt with potential for the biocontrol of Varroa lacobsom.
2. Quantify the virulence of acarine-active fungi and Bt to Varroa jacobsoni in laboratory bioassays.
3. Measure the physiological characteristics of fungal biocontrol agents and relate these to hive conditions.
4. Quantify the virulence of candidate pathogens to selected non-target and beneficial organisms.
5. Determine the persistence and spread of potential biocontrol agents within hives.

Initiate development of formulation and application strategies of potential biocontrol agents.
Project Documents
• Final Report : Screening pathogens for the biocontrol of Varroa jacobsoni.   (801k)
Time-Scale and Cost
From: 1998

To: 2002

Cost: £410,231
Contractor / Funded Organisations
Horticulture Research International, Rothamsted Research (BBSRC)
Bee Health              
Organic Farming              
Pest Control              
Varroosis (Varroa)              
Fields of Study