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Catasarcus weevil

Catasarcus spp.

 

 


Adult catasarcus weevil (Catasarcus spp.)
? Agriculture Western Australia


Description
These weevils are restricted to Western Australia and some parts of South Australia. At least 41 different species have been identified. The most commonly found species has a black and ochre stippled abdomen; the thorax is black, while the head has two ochre coloured lines running down its "snout". Overall the insect is a large robust creature, about 15 mm long. When disturbed they can "play dead", tucking their legs tightly beneath them and dropping from the leaf or branch upon which they have been feeding or resting.

 
Life cycle
As with many Australian insects, the life cycle is not fully known. Because the adults do not fly, and move about by crawling, it is unlikely that eggs are laid any great distance from the host tree upon which the adults feed. Eggs are laid in clusters just below the soil surface and the larvae feed on the roots of eucalypts. It is not known how long the larvae take to develop.
 


Eucalypt damage
? Agriculture Western Australia


Damage
On farms, most damage has been noticed on Australian native plants grown around farm buildings and along farm fences as windbreaks. Generally such plants are eucalypts. In the Esperance area the planted species most commonly attacked are tuarts, while around Albany, bluegums are often attacked. The weevils chew leaves around the edges, giving a scalloped appearance. Heavy infestations can strip trees completely, especially if they are small. The seriousness of the damage is largely a matter of opinion; some farmers claim trees are severely retarded or even killed, while others find that trees can compensate for the defoliation. Young trees are most likely to be adversely afterward. Some observations suggest that trees suffering from some other setback are most affected for example, trees suffering from water stress or nutritional imbalance.
 
Control
The need to control these weevils is uncertain. The best advice is to let individual cases be considered by tree owners, who can decide on the numbers of weevils present, the size of the trees, and the speed with which damage occurs. Few insecticides have been tested and registered for control of catasarcus.
 

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