Brown pasture looper click for html version

Summary:

Brown pasture loopers are relatively large, dark coloured native caterpillars with a characteristic looping motion. They can become an occasional pest on various crops. This generally occurs in autumn and winter when large caterpillars march from summer and autumn weeds onto newly emerged crop seedlings. Damage can be reduced by natural predators and controlling summer and autumn broadleaf weeds, particularly capeweed and storksbill. If needed, there are several insecticides registered against brown pasture loopers, although spot spaying or perimeter spraying is usually all that is required.

Occurrence:

An irregular minor pest that is native and widely distributed throughout Australia, except in the Northern Territory. They are more prevalent in high rainfall districts.

A native pest that is widely distributed throughout Australia and can become an occasional pest of broadleaf crop .

Description:

Brown pasture looper larvae are dark brown to grey with a distinctive wavy yellow line along the back either side of a conspicuous dark band. They have red colouration surrounding the breathing holes (spiracles) along the sides of the body, and can grow to 20–35 mm in length. They use their single pair of abdominal prolegs and one pair of anal prolegs to move using a series of back arches, which results in a characteristic looping motion.

Brown pasture looper larvae showing the abdominal and anal prolegs (left) and the two yellow lines running along its back (right) (Source: cesar) Brown pasture looper larvae have two bright yellow, wavy lines running along the back.

Adult brown pasture looper (Source: Copyright © Western Australian Agriculture Authority, 2015).

Lifecycle:

Brown pasture loopers have only one generation per year. Adult moths emerge after the autumn and remain active until about June. They typically lay eggs on leaves in early to mid autumn. The caterpillars that hatch from the eggs grow to full size in about two months. Once larvae reach full size in spring they pupate and remain dormant over summer. They emerge as moths in the following season.

Lifecycle, critical monitoring and management periods for the brown pasture looper (Source: cesar)

Behaviour:

Brown pasture loopers move with a looping action where the forelegs are extended to take grip then the back is arched to bring the hind legs up to just behind the fore legs. After defoliating broadleaf weeds, they can march into crops to cause seedling damage.

Similar to:

Larvae are similar to native budworm and but only have one set of abdominal prolegs.

Crops attacked:

Canola, lucerne and lupins, as well as broadleaved-weed component of pastures.

Brown pasture looper eating through broadleaved weeds in a pasture (Source: Vic Government)

Damage:

Larvae attack pastures, canola and some pulse crops, and are most damaging when caterpillars are greater than 20 mm long. They usually cause damage when they migrate from summer and autumn weeds onto newly emerged seedlings. Feeding damage to leaves and severe defoliation can occur.

Often movement of brown pasture looper from pasture to crops occurs when the broadleaf weeds on which they are feeding are killed with herbicide.

Brown pasture looper feeding on capeweed remnants (Source: Copyright © Western Australian Agriculture Authority, 2015) Monitoring:

Monitor crops and pastures soon after establishment. Brown pasture loopers are often prevalent around patches of capeweed and at the edge of crops. Older larvae can move in large numbers into crops from adjoining pastures.

Economic thresholds:

There are no economic thresholds established for this pest.

Management options:

Biological: Brown pasture looper eggs can be attacked by wasp caterpillar parasitoids. Spined predatory shield bugs and glossy shield bugs attack young larvae.

Cultural: Control summer and autumn broadleaf weeds (in particular capeweed and storksbill (Erodium spp.) within paddocks and along fencelines.

Chemical: There are several insecticides registered against brown pasture loopers in pastures and various broadacre crops. Spot spraying or perimeter- spraying is usually all that is required as this pest often moves from weedy perimeters (eg. fencelines) into crops.

There are several insecticides registered against brown pasture loopers, however spot spaying or perimeter spraying is usually all that is required.

Acknowledgements:

This article was compiled by Garry McDonald (cesar) and Sandra Hangartner. References/Further reading:

Bailey PT. 2007. Pests of field crops and pastures: Identification and Control. CSIRO Publishing, Melbourne, Australia. Hopkins, D. 1987. Brown pasture looper. FactSheet 43/85. Department of Agriculture South Australia.

Version control:

Date Version Compiled by Reviewed By February 2015 1 Sandra Hangartner and Alana Governder (cesar) and Garry McDonald (cesar) Bill Kimber (SARDI)

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