PEST

NAME
Beetles (General)
Various Beetle Species

ORDER
Coleoptera

Description of the Pest
There are many different types of beetles both adult and larvae feed and have chewing mouth parts.

     Brown (Scarb) Eucalyptus Beetle

Brown Eucalypt Beetle(Lepidiota rothei) adult is brown with hairy legs and grows to 20mm long. It has chewing mouth parts and feeds on the leaves, sometimes swarming and stripping the host tree. The lava is cream coloured curl-grubs that feed on the roots of the tree. The feeding habits of this beetle are very simular to the Christmas Beetle (Anoplognathus species), eating new shoots and leaves to the mid rib, commonly attackingEucalyptusspecies.
     
European Bark Beetle(Scolytus multistriatus) female adult is reddish up to 3mm long and lays its eggs in tunnels in the sap wood and the emerging lava tunnel through the bark forming tiny holes. This beetle is regarded as a main transmission source for Dutch elm disease that infects Ulmusspecies.

European Willow Beetle(Plagiodera versicolora) is metallic blue up to 4mm long and overwinters in the bark. During spring the yellowish eggs are laid and the emerging lava skeletonise leaves by feeding on the underside. There can be two generations per year and attack Salixspecies.

Fig Leaf Beetle     

Fig Leaf Beetle(Poneridia semipullata) is a dull brown adult has a reddish brown head and growing to 12mm (Ľin) long with prominent antennae. It deposits up to 50 eggs that are in groups on the underside of the leaf. The yellowish spiny larvae are small and appear as sawdust on the leaf. As they mature they turn blackish and grow to 12mm (Ľin) long, widest at the head.
It prefers coastal tropical to warm temperate regions and both adult and larvae feed on the leaves. The larva graze in groups skeletonising the leaves and making plants look unsightly.

Figwort Weevils generally the adult beetles are normally black to greyish white, up to 4-5mm long with one or two black circular marks where the wing cases meet. The larvae are yellowish to brown grubs with black heads up to 6mm long and have a slimy texture.

The larvae pupate in spherical cocoons that it spins and is attached to the host stems. The cocoon resembles the seed pods of Scrophulariaspecies (Figwort). Adults overwinter in leaf litter or the soil emerging during spring and lay eggs on the host plant. There is normally two generations per year.

The larvae feed on leaves by grazing the surface of the leaf eating the epidermal layer. The leaf turns brown, shrivels and dies. Many plants are susceptible, includingHibiscus, Dahlia, Vitisspecies and avocados, potatoes, sweet potatoes, rhubarb, and various weed species.


      Paropsisspecies adult and larvae

Leaf-eating Beetlesin the Chrysomelidaefamily are found throughout the world with over 3,000 species in Australia. Generally small smooth and colourful, globular or flattened up to 15mm in length with antennae one third the length of the body. Normally adults and larvae feed on the living tissue of the leaves. There are many sub-families including Sagrinae containing the larges species, Bruchinae containing larvae that eat seeds and the larges subfamily Chrysomelinae contains many species such asParopsisspecies. These beetles are characteristic dome shape and are commonly seen on Eucalyptusspecies.

     
Staghorn Beetle Damage

Staghorn Beetle(Halticorcus platyceryi) is a small rounded beetle that is black with four dull red spots on the wing covers. It has pinkish lava and both larvae and adult feed on the epidermal layer of fronds leaving small brownish sunken areas.

Wattle Blight(Paropsis orphana) adult is a light green oval-shaped beetle with white stripes on its wing covers up to 6mm long. The small lava has a tapering shape and both adult and lava feed together in groups on the surface of Acaciaspecies leaves turning them brown.

Vegetable Weevil(Listroderes difficilis) is found during cooler weather (spring or autumn). The adult brown beetle up to 19mm long with a "V" mark on its back and the eggs are laid in the soil around the base of the host plant. The cream coloured lava emerges in spring after rain and feed on the lower leaves forming irregular holes or chewing holes in stems. The lava also feed on fleshy roots boring holes into carrots. Both the adults and lava cause damage, feeding on the plant during the night and resting at the base or under ground during the day. The lavae pupate in the soil over winter.

Life Cycle
This insect has a Holometabolouslife cycle, i.e. it has alarvaland a pupal stage.

Distribution of the Pest

Beetles are found world wide.



Period of Activity
The beetles are active from spring to mid summer preferring the warmer weather.

Susceptible Plants
The beetles attack many species of trees, shrubs, ferns and small plants as in potted plants in nurseries.

Aesculus californicais attacked by the oak bark (Pseudopityophthorusspecies) and Ambrosia beetles (Monarthrumspecies). These insects overwinter under the bark and when active the boring holes are a identified with would just war of bleeding, frothy or bubbling. The trees will appear stressed with less foliage and a lack of vigour. Control methods include the digging out or and removal of the lava.

Anemone andClematisspecies are attacked by the Black Blister Beetle(Epicauta pennsylvanica) which eats the leaves and flowers.

Callistephusspecies are attacked by the Asiatic Garden Beetle(Autoserica castanea) that chews on the foliage at night and hides in the soil or around the base of the plant during the day.

Caryaspecies are attacked by the Bark Beetle(Scolytus quadrispinosus). The tiny adult beetle is brown up to 5mm long and the legless lava tunnel the bark and sapwood where it over winters, causing ringbarking. Twigs and small branches wilt and die.
This species is also attacked by the Twig Girdler(Oncideres cingulate),a reddish beetle that is 20mm long and produces small lava that girdles twigs by tunnelling, where it overwinters. This weakens the twigs causing them to snap off or results in ringbarking.

Cheiranthusspecies may be attacked by the Red Turnip Beetle(Entomoscelis americana) which is bright red with black markings in its head and wing covers and feeds on the foliage.

Eucalyptusspecies and other plants in the Myrtaceaefamily are attacked by the Flower Scarab Beetle(Protaetia species) a rounded brownish adult that grows to 20mm long, feeding solitary on flower pollen or new growth causing wilting and twig dieback. The insect is found from tropical to temperate regions and is regarded as a minor pest. Eucalyptus are also attacked by Leaf-eating Beetleswhich eat irregular pieces from the margins.

Damaged Margins on Eucalyptus by the Leaf-eating Beetles

Proteaspecies are also attacked by the Flower Scarab Beetle.

Ficusspecies      Damaged epidermal layer

Ficus species are susceptible to the Fig Leaf Beetle (Poneridia semipullata). Both adult and larvae feed on the leaves eating the epidermal layer and making the plant in large infestations look poorly.

Nothofagus obliquaand Nothofagus glaucaare attacked by the Wood Borer of Coigue(Holopterus chilensis) a native of the Argentinian and Chile mountains. This beetle bores into the base and stems of the tree causing damage to the cambium layer resulting in dieback of branches. In a forest situation it is difficult to control but on individual species the beetles maybe dug out.

Ulmusspecies are attacked by the European Bark Beetle and theLeaf Beetle(Galerucella luteola) adult, which eats areas out of new leaves.

Samanea samanfruit pods are attacked when the burchid beetle (Merobruchis columbinus) oviposits in the immature fruit. The lava can kill or damage up to 75% of the seeds but is not commonly a major problem.

Solanum tuberosumis attacked by wireworm (Agriotes species). The larvae of this beetle, tunnels into the tubers. It is best controlled by planting in the soil which has not been affected previously.

Ulmusspecies are attacked by the European Bark Beetle and theLeaf Beetle(Galerucella luteola) adult, which eats areas out of new leaves and its lava skeletonise the underside of mature leaves later in the season.

Damage Caused
Some beetles and their larvae may eat the leaf surface in bands leaving the veins intact while other larger beetles tend to eat leaves from the margins preferring new shoots.

Beetle damage

Cultural Control
Small infestations may be removal by hand where possible.
The Brown Eucalypt Beetle will not fly during the night and if disturbed by shaking or beating the tree, fall to the ground where they can be collected on a tarp that is laid under the tree then destroyed. This method also works on the Flower Scarab Beetlethat fall to the ground pretending to be dead when disturbed.

BiologicalControl
Beetles are eaten by predators including birds, frogs, and lizards and are attacked by parasitic wasps.

Chemical control
Will vary with the pest, the plant on which it is found. The part of the plant being attacked.

Note
It is your responsibility by law to read & follow the directions on the label of any pesticide
Amendments by B. Sonsie Dip Hort Sc Burnley