Project: 1999-04. Report - Biological Control of Broom: Host Range Testing of the Broom Gall Mite Aceria genistae
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Date: November, 2000 Author: S. V. Fowler, H. Gourlay, A. W. Sheppard and P. Hodge Publication: Landcare Research Contract Report LC0001/44 Project reference: 1999-04 Full report is available from: |
Executive summary:
Project and Client
Landcare Research was contracted by the Forest Health Research Collaborative (FHRC) to carry out host range testing of the gall mite, Aceria genistae, a potential biocontrol agent for broom, Cytisus scoparius, in New Zealand from June 1999 to October 2000
Objectives
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To provide New Zealand test plant species for the Commonwealth Scientific and Industrial Research Organisation (CSIRO) at their quarantine containment facility in Canberra.
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To liaise with, and subcontract, CSIRO to carry out the host range testing of the broom gall mite using the colony of the mite that CSIRO has established in their quarantine facility.
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To report the findings to the Forest Health Research Collaborative.
Methods
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A test plant list of 15 species was devised, comprising six species of New Zealand native Fabaceae, eight species of Fabaceae of ornamental or economic significance to New Zealand, and broom sourced from New Zealand. These plants were shipped to CSIRO for testing in their secure quarantine facility.
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Host range testing was largely completed by CSIRO, with a few results still pending or awaiting tests to be set up or repeated. CSIRO will complete these remaining tests and report the results to Landcare Research.
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No broom gall mites survived or formed galls on any of the plants tested, other than the broom controls.
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Five replicate tests, using five broom plants as controls, were carried out for each test plant species.
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Broom galls were scored for number of mites present and then distributed among the plants.
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Tests were carried out in a high-security quarantine under controlled light and temperature for up to 5 months.
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All fresh green buds on test plants were dissected to look for live mites.
Main Findings
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In all tests, multiple galls were produced on the broom controls demonstrating that the mite transfer technique is highly reliable.
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Taxonomic problems in the Aceria genistae species complex were highlighted during the testing, and are being investigated genetically by CSIRO as part of a separate project.
Recommendations
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CSIRO should complete the host range testing with the remaining plant species, by repeating the test with Chamaecytisus palmensis (New Zealand material), setting up tests with Medicago sativa and Trifolium repens, and running the test with Laburnum sp. to completion.
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CSIRO should report the results of the above tests to Landcare Research, who will inform FHRC,
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Once the uncertainties concerning the taxonomic identity of the broom gall mite have been resolved, Landcare Research should consider the gall mite for inclusion in an application for release to the Environmental Risk Management Authority via a suitable applicant group.
Full report is available from:
Landcare Research New Zealand Ltd
Private bag 92170
Auckland
New Zealand
