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Biological control of Paterson's curse with the stem-boring beetle | LC0159 |
Keith Turnbull Research Institute, Frankston
December, 1998 |  |
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Common name
Paterson's curse stem-boring beetle
Scientific names
Phytoecia coerulescens (Scopoli)
Family Cerambycidae, Longicorn beetles
Background
Paterson’s curse, Echium plantagineum L. is a noxious weed of European origin found through much of Victoria. A national program for the biological control of Paterson’s curse, led by CSIRO Division of Entomology, involves the establishment of populations of the weed’s natural enemies in suitable infestations and the redistribution of them to new sites as populations increase. One of these natural enemies is the Paterson's curse stem-boring beetle, Phytoecia coerulecsens.
Description
Adult - Size highly variable (12 to 25 mm long) depending on the host plant size and larval competition within the root. Colour varies from grass green to steel blue. Antennae are nearly as long as the body, curved and mobile so that they can be directed backwards above and parallel with the body.
Figure 1. Adult stem-boring beetle.
Egg - Yellow, 2 to 3 mm long, cylindrical, inserted in a wound made by the female in the epidermis of the basal third of the flowering stem.
Figure 2. Larva of the stem boring beetle.
Larva - Elongate, cream-coloured grub, up to 25 mm long, straight-bodied, distinctly segmented, no legs. Head brown and somewhat sunken into thorax. Mandibles large and stout.
Pupa - Cream-coloured, enclosed in a cell at the base of a hollowed-out stem which is plugged with stem fibres.
Life cycle
Females begin laying eggs in spring when the plant is bolting. Eggs are laid on the basal third of the flowering stem and take approximately one week to hatch. During development of the first three larval stages (known as instars), the larva mines upwards and feeds on the growing stem. Once mature, the final instar larva bores down the stem, which it girdles 4 to 10 cm above the ground, and continues into the stem base or root stock. The mine is plugged at each end with fibres from the stem, forming a cell within which a single larva remains dormant through the winter.
Pupation occurs in early spring. Adults emerge from spring to early summer and feed on flowers and stem leaves of Paterson’s curse. Mating and egg-laying commences soon after emergence.
Impact
Damage is most severe to small, thin-stemmed plants. The boring of larvae in stems just large enough to support a larva to maturity may cause the stems to be completely eaten out and girdled, before any seed can be produced. There is little effect on large, thick-stemmed plants other than stems becoming weakened and falling over.
Releases
Releases of the Paterson's curse stem-boring beetle were first made in Victoria in December 1998, focused on North East Victoria where Paterson’s curse is a major problem. Release sites are selected by researchers and local DNRE staff in consultation with land owners and Landcare groups.
Releases are targetted at dense and persistent infestations of Paterson’s curse with a low priority for control by other methods. Release sites need to be part of large infestations, or connected to them, so that the beetle can spread easily when its population increases.
Integrated control
Four other natural enemies of Paterson’s curse have already been released in Victoria. The leaf mining moth, Dialectica scalariella, was the first biological control agent to be released, in 1988. The crown weevil, Mogulones larvatus, was released in 1993 and the root weevil, M. geographicus, was released in 1996. The fourth agent, the Paterson’s curse taproot flea beetle, Longitarsus echii, was also released in 1996. The combined effects of these agents is expected to have a significant impact on Paterson’s curse infestations.
Biological control is not appropriate for many infestations of Paterson’s curse. A local integrated weed management plan should be developed for each particular area. The plan should identify opportunities for integrating all available control options, including biological control, in the most environmentally sensitive, economic and efficient manner.
Biological control will not totally eradicate a weed but may reduce its spread and density. In some cases control is achieved to a level where the weed is no longer considered a problem. More commonly, other methods are still required to achieve the desired level of control. Biological control should not be considered the complete answer to a Paterson’s curse problem. It is a technique that can be used in conjunction with other control measures in the integrated management of this weed.
Further information
Landcare Note. Biological control of Paterson’s curse using the leaf mining moth, Dialectica scalariella.
Landcare Note. Biological Control of Paterson’s curse with crown and root boring weevils.
Landcare Note: Biological control of Paterson's curse with the taproot flea beetle.
Landcare Note. Paterson's curse.
Landcare Note. Paterson's curse identification.
For further information please contact your local Catchment Management Officer of the Department of Natural Resources and Environment or
Keith Turnbull Research Institute,
PO Box 48 Frankston, Victoria, 3199.
Tel (03) 9785 0111 Fax (03) 9785 2007
References
Kirk, A.A. and Wapshere, A.J. (1979). The life history and host specificity of the Echium borer, Phytoecia coerulescens [Col.: Cerambycidae]. Entomphaga 24, 423-430.
Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious Weeds of Australia. Melbourne, Inkata Press.
Acknowledgements
Prepared by Kerry Roberts, Tom Morley and Ian Faithfull, 1997. Photographs by Blair Grace. Revised 1998. Biological control of Paterson's curse is partly funded by The Woolmark Company and Meat and Livestock Australia and is a project of the Cooperative Research Centre for Weed Management Systems.
This note replaces note number BC0025
The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
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