Leafminer

Perthida glyphopa

Family: Incurvariidae

Order: Lepidoptera

Description:

Adult

Colour - Grey brown.

Body - 6 mm long. Stout. Long hair scales.

Wings - 2 Pairs. Membranous. Hairy. Slender.

Mouthparts -

Antennae - 3 segments.

Legs - Broad overlapping scales. Feet (Tarsi) have 5 segments.

Head - Broad overlapping scales. Large rounded compound eyes.

Thorax - Broad overlapping scales. 3 segments. Front segment much smaller. Hairy

Abdomen - Broad overlapping scales. 7-11 segments. Spiracles on segments 1-7. Hairy

Egg -

Habits - Can't fly when cold. Run up and down leaves and twigs on warm autumn days.

Caterpillar

Colour - Cream

Body - Cylindrical. Up to 10 mm long.

Mouthparts - Chewing.

Antennae - Short. 3 segments.

Legs - 3 pairs of thoracic legs (with 5 segments) near the head and prolegs near the tail.

Head - Hard.

Thorax - 10-11 segments. Spiracles on segments 1 to 8. Prolegs on segments 3-6 and 10.

Abdomen -

Habits - Herbivorous. Mines the leaf leaving a pale thin skin on the top and bottom sides of the leaf.

Pupa - In ground over spring and summer.

Biology:

Life Cycle:

Moths fly from April to May and lay eggs singly on underside of leaves. Eggs hatch and young caterpillars mine leaves from May to September. The larva then constructs an elliptical case by cutting 5 mm oval section from the top and bottom skins of the leaf and joining them with silk. This drops to the ground and the larva buries it 20-30 mm deep and remains inside the case until February. It then pupates until emergence in April or May.

Habitats:

Origin and History:

Distribution:

Significance:

Caterpillar feeds by mining between the leaf surfaces of eucalypts, especially jarrah, leaving a blister like cavity with droppings and often the caterpillar inside. Many of these may be on each leaf and this gives the tree a scorched appearance. Attacks are usually worst along forest edges, roadsides and in parkland cleared areas.

Management and Control:

Insecticides are relatively ineffective on a large scale. Systemic insecticides injected into the trunk of trees are effective for small plantations.

For stem injection, mix 10 mL dimethoate400 with 10 mL water. Drill 12 mm diameter holes angled downwards at 45 degrees about 25 mm deep into the sapwood at 100 mm spacings around the trunk and about 250 mm above ground level. Inject 3 mL of the dimethoate mix into each hole. Plug the holes with putty a few hours later to prevent decay

Parasitic wasps and birds attack the larva.

Related Species:

Similar Species:

References:

CSIRO. The Insects of Australia. Melbourne University Press. (1991) p844.

WADA. Insects and Allied Pests of Extensive Farming. Department of Agriculture - Western Australia Bulletin No. 4185. p88.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.