Biological Control of Paterson's Curse with the Flower Feeding Beetle
Note Number: LC0165
Published: February, 1998
Common and scientific names
Paterson’s curse flower feeding beetle
Meligethes planiusculus (Heer)
Background
Paterson’s curse (salvation Jane), Echium plantagineum, is a noxious weed of European origin found through much of Victoria. A national program led by CSIRO Division of Entomology and in collaboration with the Department of Natural Resources and Environment Victoria (NRE), NSW Agriculture, Agriculture Western Australia and the South Australian Research and Development Institute involves the establishment of populations of the weed’s natural enemies in suitable infestations and redistribution to other sites as populations increase. One of these natural enemiesis the Paterson’s curse flower feeding beetle.
Keith Turnbull Research Institute has developed a mass rearing program to rear and release the flower feeding beetle onto Paterson’s curse infestations throughoutVictoria.
Description
Adult: 2 mm long, broad and flattened, with shortened wing covers, exposing the tip of the abdomen, shiny black, active flyers at temperatures around 25 oC and above (figure 1). Adults are generally smaller than the Paterson’scurse flea beetles and do not jump like the flea beetles.
Egg: 0.6 mm long and 0.25 mm wide, white to opaque incolor. Laid in the terminal buds of the flowering cymes.
Larva: Elongate, subcylindrical, white to light gray incolor, with a small light brown head (figure 2).
Life cycle
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Figure 1: Adult flower feeding beetle, Meligethes planiusculus |
The flower feeding beetles have 1 to 2 generations per year. Adult beetles are dormant over winter and become active in spring on the developing flower stalks. Here they feed, mate and lay eggs. On average a female beetle lays around 90 eggs over a period of 31 days. Eggs take around 4 to 6 days to hatch. The larvae then bore through the calyx and petal to feed on anthers, pollen and ovules within the unopened flower bud. Final instar larvae are mobile and move between flowers on a cyme, feeding on the developing seed. Larvae complete development in 14 to 20 days, then drop from the flowers to pupate in the leaf litter or soil. Adults emerge in around 10 days and return to their host to feed on pollen, developing ovules and maturing seed in open flowers. Adults that emerge before the longest day of the year may oviposit, leading to a partial second generation. At the end of the flowering period adults pass the remainder of the summer and the following winter in aninactive state away from their host in the leaf litter or soil.
Impact
Feeding damage to the flowers and developing seed byadults and larvae results in reduced seed production.
Releases
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Figure 2: Beetle larvae feeding in a Paterson’s curse flower |
The Paterson’s curse flower feeding beetle has been released at sites in New South Wales and releases in Victoria will begin in spring 1998. Nursery sites are selected by researchers and local NRE area staff in consultation with land owners and Landcare groups. A release site should have a dense and persistent Paterson’s curse infestation and be connected to neighbouring infestations so that the beetle can disperse more readily. The site should have a low priority forcontrol by other techniques.
Feeding damage by adults and larvae to the flowers and developing seed results in reduced seedproduction.
Integrated control
Four species of insect which attack Paterson’s curse have already been released in Victoria. The leaf mining moth, Dialectica scalariella, was first released in Victoria in 1988 and was well established by 1992. The crown boring weevil Mogulones larvatus has been widely released since 1994 and redistributed from 1996 onwards. The root boring weevil Mogulones geographicus was first released in early 1996 and the taproot flea beetle Longitarsus echii was released in late 1996. The complementary effects of these agents are expected to make the weed lesscompetitive.
Biological control cannot totally eradicate a weed but can reduce the spread and density of infestations. In some cases control is achieved to the level where the weed is no longer of concern and no other control is necessary. More commonly, other methods are still required to achieve thedesired level of control.
Biological control should not be considered the complete answer to a Paterson’s curse problem. It is a technique that should be used in conjunction with other control measuresin an integrated management plan.
Further information
Biological Control Notes No. 2. Biological Control of Paterson’s Curse Using the Leaf Mining Moth, Dialecticascalariella.
Biological Control of Paterson’s Curse with Crown andRoot Boring Weevils.
Landcare Note (LC0173): Paterson’s Curse.
Landcare Note (LC0159): Biological control of Paterson’scurse with the stem boring beetle.
Landcare Note (LC0155) Biological control of Paterson’scurse with the taproot flea beetle.
For further information on the biological control of Paterson’s curse please contact your local Catchment Management Officer of the Department of NaturalResources and Environment (NRE) or:
Keith Turnbull Research Institute,
PO Box 48, Frankston, Victoria, 3199.
Tel (03) 9785 0111 Fax (03) 9785 2007
email K.Roberts@nre.vic.gov.au
CSIRO Division of Entomology
GPO Box 1700, Canberra, ACT, 2601
Tel (06) 246 4406
Fax (06) 246 4177
Acknowledgments
Biological control of Paterson's curse is partly funded by the International Wool Secretariat and the Meat Research Corporation and is a project of the Cooperative Research Centre for Weed Management Systems.
Prepared by Kerry Roberts & Tom Morley.
It was reviewed by:
Keith Turnbull Research Institute, Frankston
