Shoalhaven and South Coast farmers are being urged to be on the lookout for signs of damage and the presence of fall armyworm larvae in summer crops following the recent trapping of moths in NSW.
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The moths were first trapped near a sorghum crop near Moree during routine surveillance of the early warning trapping network established by NSW Department of Primary Industries (DPI) and Local Land Services (LLS).
Fall armyworm is an insect pest that poses a serious threat to a range of crops.
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While it has been found in a small number of locations, it is anticipated that migratory flights of the pest will occur annually across NSW and fall armyworm may establish in some of the warmer parts of the state.
Farmers in the South Coast region need to be on the lookout for signs of fall armyworm, which include windowing of leaves where larvae have hatched and small shot holes as leaves expand, caused by larvae feeding in the developing leaf whorl.
The best way to minimise the spread and impact of the pest is to identify the signs and symptoms early.
Fast action to manage small larvae is recommended by NSW DPI and Local Land Services (LLS) to maximise control and help minimise further spread by restricting local infestations.
Anyone who suspects the presence of fall armyworm should immediately call the Exotic Plant Pest Hotline on 1800 084 881.
For small larvae, the Department of Primary Industries and Local Land Services recommend retaining samples with food, such as host crop leaves, and allow them to grow to enable photographs to be taken.
In most cases, NSW DPI will be able identify larvae from clear photographs which can be sent via an online form or to biosecurity@dpi.nsw.gov.au with your contact details.
DPI continues to work with potentially affected industries providing free insect diagnostics for suspect fall armyworm moths and larvae, advice on control and chemical management options.
Farmers should contact their LLS staff or regular agronomist for advice on fall armyworm management.
Description - Fall armyworm is the name commonly attributed to the larval stage of the moth Spodoptera frugiperda.
Other Spodoptera species already found in Australia include the lawn armyworm and the dayfeeding armyworm.
The fall armyworm life cycle has an egg stage, five to six caterpillar (larval) stages, a pupal stage and an adult moth stage.
The larval life cycle stages cause widespread damage to crops through feeding.
Fall armyworm eggs are usually laid on the under surface of leaves in clustered masses of 100-200, covered with a 'felt like' layer of scales. The eggs are pale yellow.
Small fall armyworm larvae are usually light green to brown, with a dark head capsule. Evidence of crop damage, such as the skeletonising of leaves (or "windows") is often more readily visible than the presence of larvae.
Large fall armyworm larvae grow to three to four centimetre, becoming darker as they mature, with pale white stripes along the length of the body.
The large caterpillars have a pale inverted "Y" shape between the eyes.
Two dark spots with dark spines occur on each body segment on the upper body surface, with four black spots arranged in a square on the last abdominal segment.
Fall armyworm larvae normally pupate in the soil. The pupae are shiny brown and between 1.3 and 1.7cm long.
Adult fall armyworm moths measure three to four centimetres from wingtip to wingtip.
Female moths are slightly larger than males, although both sexes have a white hindwing with a dark-brown margin.
Male moths are more patterned and have distinct triangular white spots at the tip and near the centre of each forewing.
Fall armyworm can complete its life cycle within 23-27 days (from egg laying to the emergence of adult moths), when suitable temperatures and host plants are present.
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