Loopers

Loopers can occur anytime throughout the growing season. Normally, they feed almost exclusively on leaves and don't cause significant damage, but under some conditions, populations can flare as high as 150 per square metre.

Scientific name

Green loopers

Achaea janata (Castor oil looper)
Thysanoplusia orichalea (Soybean looper)
Chrysodeixis argentifera (Tobacco looper)
Chrysodeixis eriosoma (Vegetable looper)

Brown loopers

Mocis alterna (Bean looper)
looper Ciampa arietaria (Brown pasture)
Mocis frugalis (Sugarcane looper)
Mocis trifasciata
Pantydia spp.

Other names

Bean loopers are also known as mocis

Description

  • Eggs are pale yellow-green and slightly flattened.
  • Larvae can grow to 50–60mm long.
  • Green loopers are green with white and/or dark stripes.
  • Brown loopers are slightly smaller.
  • Moths are various shades of brown with a range of patterns on their forewings.

May be confused with

Loopers can be distinguished from helicoverpa by:

  • their 'looping' action when walking
  • their body, which tapers to the head
  • only 2 pairs of hind legs (helicoverpa has 4).

Distribution in Queensland

  • Widespread throughout northern cropping areas (including northern New South Wales); more common in coastal regions.
  • Brown pasture looper occurs in all winter oilseed areas.
  • Some green loopers have been reported in Tasmania.

Life cycle

Looper eggs hatch in 3–6 days. Larvae take 2–3 weeks to develop through 6 larval stages before pupating under leaves in a loose silken cocoon.

Monitoring and thresholds

  • Inspect crops weekly during the vegetative stage and twice weekly from very early budding onwards until crops are no longer susceptible to attack (late podding).
  • Use beat sheet sampling as the preferred method for looper larvae.
  • Scout for looper eggs and moths to pinpoint the start of infestations and to increase the success of biopesticides such as Bacillus thuringiensis (Bt).
  • Consider control if leaf loss is likely to exceed 33% in the vegetative stage, or 20% from flowering onwards.

Hosts

  • Bean, soybean, tobacco and vegetable loopers occur in soybean, mungbean, navy bean, azuki bean. Soybean looper is also found in sunflowers.
  • Castor oil looper and Pantydia spp. occur in soybean.
  • Cotton looper occurs in cotton.
  • Brown pasture looper occurs in canola, lupins and broadleaf pastures.
  • Sugarcane looper are occasionally found in soybeans but prefers grasses.
  • Mocis trifasciata are reported in cowpeas in North Queensland and soybeans at Bundaberg.

Natural enemies

Loopers in summer pulses are attacked by numerous predators and parasites.

Damage

Larvae are mainly leaf feeders but can occasionally feed on pods or seeds.

Looper damage is angular whereas helicoverpa damage is rounded.

Control measures

  • Loopers appear susceptible to insecticides used for helicoverpa control, with the exception of Gemstar® and Vivus® (NPVs—nucleopolyhedrovirus).
  • Bt-based pesticides are far more effective against loopers than against helicoverpa but cover thoroughly for best results. Target larvae less than 12mm long.
  • Vigorously growing plants are better able to compensate for flower and pod damage, and damaged leaves are replaced more quickly.

More information