In this section:
Salvation Jane
Biological control: what is it about?
The biological control of Salvation Jane aims to limit the dominance of the weed by reducing the vigour and size of the plants and thereby reducing the quantity of viable seed produced. Smaller and fewer plants means that other more palatable pasture species or native plant species are able to compete more successfully.
Some of the insects do have the potential to cause some plant mortality but it is important to remember that biological control is not an eradication program. Biological control is a long-term commitment and for Salvation Jane biocontrol it can take up to 7 years for control to begin to be effective. As with most plant predator relationships the insects will never completely wipe out their food source. The intention is to reduce plant numbers and size so that the weed is no longer a major plant pest.
Biocontrol is a tool for producers to use in integrated weed management. Salvation Jane biocontrol can supplement conventional control methods when used in difficult to reach areas such as rocky outcrops, steep slopes and watercourses. Lately we have also seen good results when Salvation Jane biocontrol is combined with grazing.
Suite of insects
The four main insects we are currently focusing on are the:
- crown weevil Mogulones larvatus
- root weevil Mogulones geographicus
- flea beetle Longitarsus echii
- pollen beetle Meligethes planiusculus.
Crown weevil (Mogulones larvatus)
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Crown weevil larvae feed in the growing rosette. They are best suited to areas that have a March/ April rainfall break. It is not as tolerant to grazing as other insects but is the only insect to date to have killed plants in South Australia. Crown weevil fact sheet (.PDF 398.3KB) |
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Root weevil (Mogulones geographicus)
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Root weevil larvae bore into the primary root, reducing the uptake of water and nutrients. It copes with a slightly later rainfall break in April/ May. Larval attack in the root makes it more tolerant of grazing. Root weevil fact sheet (.PDF 592.3KB) |
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Flea beetle (Longitarsus echii)
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Flea beetle larvae attack the primary and secondary roots, reducing the uptake of water and nutrients. It becomes active until June/ July so it copes well with late rainfall. Most of the lifecycle is underground making it very tolerant to grazing. Flea beetle fact sheet (.PDF 467.8KB) |
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Pollen beetle (Meligethes planiusculus)
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Pollen beetle adults and larvae feed on the female part of the flower and immature green seed, reducing the contribution to the soil seed store. Interstate evidence suggests that this beetle prefers early consistent rainfall that will extend flowering allowing multiple generations to be produced. Pollen beetle fact sheet (.PDF 581.0KB) |
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Lessons learnt
The leaf-mining moth Dialectica scalariella was released in 1989 but in Australia the damage was generally not severe enough to affect any kind of control. In South Australia biological control of Salvation Jane with the current suite of insects started in 1995. In the first few years releases of 50 insects (25 male, 25 female) were made at locations around the state. Since this time we have learnt that these very small initial populations can establish but the risk of failure is high and the establishment time is longer. We now do releases of 1000 insects and have since had greater success.
We are also more selective about the sites we choose to release insects at, preferring sites where nursery areas can be set aside and stock excluded for two to three years. Site selection also involves a better matching of the insects preferred environment and grazing tolerance, with some insects preferring early rainfall breaks than others and some coping better with grazing pressures.
Salvation Jane biological control release sites
The distribution of Salvation Jane biocontrol insects is displayed in the maps below. They include all the releases up to and including 2004.
South Australia (.PDF 601.5KB)
South east of South Australia (.PDF 309.0KB)
Central region of South Australia (.PDF 334.1KB)
Mid north of South Australia (.PDF 438.0KB)
Partners
Australian Wool Innovation and Meat & Livestock Australia fund the current national redistribution program for Salvation Jane biocontrol. The national program brings together NSW Department of Primary Industries, Victoria's Department of Primary Industries, Western Australia's Department of Agriculture, SARDI and the CSIRO.
In recent years the Cooperative Research Centre (CRC) for Australian Weed Management and the Animal Plant Control Commission have provided grants for local Animal and Plant Control (APC) Board authorised officers to take up some of the work of redistribution and monitoring of release sites across the state.
Contacts
If you would like to participate in the program and have Salvation Jane biological control insects released on your property in South Australia contact your local Animal and Plant Control Board Authorised Officer or Ken Henry.
Newsletters
SARDI has produced the Biological Control of Salvation Jane Newsletter to keep farmers and the various co-operators informed of progress of the biocontrol of Salvation Jane in South Australia.
