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LEAF The adults overwinter under bark, in crevices or in (COLEOPTERA: CHRYSOMELlDAE) leaf litter and emerge in early spring to start feeding. When the weather is warm enough they start laying Oarren Waterson and Chris Ann Urquhart eggs in various patterns on stems, new leaves or

5 T • T I shoots (Figs 1 and 2). INTRODUCTION FORESTS More than 3000 species of chrysomelid are found in Australia, most of which are never likely to achieve pest status. All known species feed on plant tissues; the adults generally feed on leaves, but the larvae may feed on roots, young stems, leaves, new shoots, flowers, fruits, seeds or leaf litter, depending on the species. Many species in this family have been introduced from overseas to control noxious weeds such as St John's wort, ragwort, lantana and alligator weed. One native species MOllo/epta australis (monolepta beetle or redshouldered ) feeds in swarms and has become a serious pest of a wide range of horticultural and field crops and ornamental plants. It also attacks eucalypts.

The group of leaf beetles covered by this leaflet are sometimes called tortoise or 'paropsine' beetles and look rather like large ladybirds. They feed mainly on the Figure 1. Female leaf beetle with eggs. newly developing foliage of eucalypts. The damage caused by these beetles is far more significant than that caused by Christmas beetles, because both larvae and adults feed fro m late spring to early winter, while Christmas beetles feed only as adults, and early in the season, allowing the trees to produce new leaves and store food reserves before winter.

LIFE HISTORY AND BIOLOGY

Several paropsine genera (groups of related species) contain species which are known pests. These genera include ClIrysophthnrta ( leaf beetles), Paropsis (including the eucalyptus tortoise beetle P. ntomarin), Paropsisterna, and Trnchymela. However, the life histories of these species are basically similar. Figure 2. ESg c1l1sters of two species. The larvae hatch from the eggs after 7-14 days. They When fully grown, three to four weeks after hatching, start to feed, and pass through four larval stages. The the larvae drop to the ground, where they burrow into larvae are caterpillar-like, but have only three pairs of the soil and pupate below the surface, before emerging legs. They grow to a length of 10-15 mm. Different as adult beetles. species vary in shape and colour, ranging from cream to dark brown, often with dark or light markings (Figs 3 Adult beetles are 5-10 mm long, oval to round, and and 4). dome-shaped, not unlike ladybirds (Fig. 5). They often have brilliant or metallic, species-specific colour patterns, but these tend to fade after death, making identification difficult.

Figllre 3. Larmc 011 leaf.

Fig 11 re 5. Adult beetle all leaf.

A female beetle can lay a series of egg batches over several weeks, so that all stages of the may occur on the tree at the same time during the summer months. e There are usually two genera tions per year on mainland Australia.

DESCRIPTION OF DAMAGE Paropsine beetles and their larvae are active from late spring until early winter. Adults feed alone around the edges of leaves, producing a scalloped effect, but most damage is caused by the larvae. About ninety percent of the damage caused by larvae is done by the third and fourth stages (Fig. 6). Fig 11 re 4. Larvae 011 leaf. The young larvae prefer to feed on soft new leaves and Paropsine larvae feed in groups during all four stages. shoots and when these ha ve been ea ten, they move on to These groups can contain all four stages, and sometimes older leaves, causing significant damage. All eucalypts more than one species. When the larvae are disturbed, are attacked, but young trees seem to be preferred and paired glands may emerge from the tip of the abdomen, these are often completely defoliated, substantially and emit defensive substances. reducing growth and sometimes causing tree death.

2 has occurred. Constant monitoring of plantations is necessary for good integrated control; as there is approximately three weeks to prepare for spraying after the first appearance of adults in spring.

In Tasmania! aerial spraying has sometimes been necessary} and good results have been achieved with synthetic pyrethrOids. However, aquatic fauna are very sensitive to these chemicals. Consequently, this opti<:m should not be considered unless there are exceptional .circumstances, and' never near watercourses. Advice should be soughtfrom StateForests on the most suitable sprays to use, amI consult Leaflet Cl - Control of on eucalypts,with regard to q,ppncation ra!es.

I . A badteritl.:rn, Badll~s thu~in.giensis, strain FI san diego~' r is ! ~,I ,11QW 1;JeiIig dE;:!veloRed foi' l:fse against be~tles, arid this, '.1 may-eventually ,offer an environmentally acceptable .. c~ntt,ol,. '··d; .',,', " , '.' , . , .' :' ...... ""--:----,------' ~L~---:--:-_-;---:"'~c-:--:;---::- , , . Pigitre6. Typical damage caused, by 1{11'Vl1e., LJnfotturialely, 'littlt? is Rnerwn about the~SFeciE;:!s:ukeiyt0' ...' :There is' evicr$lce that $ome species have distinct h0st .. ha~e':the gre~test:,eff~cfon~uci1ypt pJqntatlons:in New, {r~e.p~efete~c~s, a:Ithough mostwiIi eat?- Wid~ fa:ngeof, ,Sovth WaI~s; anc;l f~t;d:bacK flloin.gtbW~l:'S is' essenfici:I-to .€"l!,cruyp'ts. " .. helpd~veIo~'better G0n~01s.; . . " '. . .

CQNTROI.: : F:URTIiJ:R'INFORMA110tt UncleI' ~a~ralc~l1diti~ns, ,n10~t populafien§ are welL:, . Carne,.P ;B." ahd K.t. Taylor. (i97S). Insect pests, C;:h. 7iri .c<,;>ntr6lie<1 by b~rds, (li~e~s~, 'par~sffic :J)i~s' anc~' wasps. ,', . Eucalypts f9r Wood Production. (Ells W.E. Hill~ and: An. -However; in plantations it may be'necessary:to red,uce 'Brown). ,CSIRO, Austi:alia: " " , . , , .d~llp.ageby sprayIng insectici4,es. :Exp'ede~Ge flq? sh~wn' .tIi:aHl1e-.bes! time ~bd? this is during fhe fitst a').1.d se

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