Loopers

Scientific name

Two species of looper occur on lychees and longans:

• castor oil looper, Achaea janata
• conspicuous looper, Oxyodes tricolor.

Various insects species including Cleora inflexaria (grey looper), Lophodes sinistraria (brown looper) and Ectropis sabulosa (ectropis looper) damage avocado.

Description of adult

The moth of the castor oil looper is 25mm in length and 55mm across the out-stretched wings. The wings are usually folded roof-wise at rest. The forewings are mottled dark brown with a darker wavy dark brown line across the wing about a third of the way along the wing. The hind wings are dark brown with a purple tinge. There is a matching white band across the wing and 3 evenly spaced white blotches along the outer margin of the wing.

The moth of the conspicuous looper is similar in size and shape to the castor oil looper. The forewings are dark brown in colour with a 2mm diameter clear spot about a third of the way out from the wing base. The frontal half of the hind wing is dark brown to black and the remaining half is orange. The head and thorax is brown and the abdomen orange.

Immature stages

The mature castor oil looper is 60mm long, has both light and dark forms and has 2 black spots near the head. The conspicuous looper has a mainly black body, yellow legs and 2 red spots near the head.

The looper larvae found on avocado trees are about 35 to 40mm long. When disturbed, the larvae stretch out and stiffen to look like a twig.

Life history

Little is known of the life history of either species found on lychees and longans. However the egg stage probably lasts about 5 days, the caterpillar (looper) stage about 4 weeks and the pupal stage about 10 days. The moth of Oxyodes tricolor over-winters in large numbers, clustered on shrubs in the tropical lowland forests of North Queensland. Large flights of the species have been recorded in southern Queensland in March–April.

Distribution

Throughout Queensland.

Host range

• Castor oil looper: lychee, longans, castor oil, cocoa and tamarillo.
• Conspicuous looper: lychee, longans, cocoa and tamarillo.

Loopers also attack avocado and papaya.

Damage

Sporadic minor pests throughout Queensland.

Larger caterpillars can consume whole leaves and trees may be stripped of foliage. Loopers can cause considerable defoliation of lychees and longans in all areas and in north Queensland are particularly active after the wet season. Regular inspection, particularly of young trees, is necessary to detect infestation early and to enable control measures to be applied before serious damage is done.

Some species will also damage fruit of the host plant.

Control

For lychees and longan crops, examine 5 flushes on each of 20 trees widely spaced throughout the crop. Spray if more than 50 out of 100 flushes are infested and have lost more than 30% of leaves. Check for loopers and tattered leaves on small trees with new growth. Control is generally only necessary on small trees if critical growth flushes are being destroyed. Unless more than 30% of the leaves are lost, sprays should not be applied since the tree can sustain considerable leaf damage and natural control agents will limit looper populations.

Treatment of avocado trees is generally only necessary where leaf damage is severe and fruit are being damaged. Where required, spray with an appropriate chemical. Regularly monitor the orchard so that action can be taken before damage gets too severe. Avoid continuous use of insecticides that are disruptive to beneficial insects.

Chemical

Spray with a registered chemical when the infestation reaches the threshold level.

Check the Australian Pesticides and Veterinary Medicines Authority database for chemicals registered or approved under permit to treat this pest on the target crop in your location. Always read the label and observe withholding periods.