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Further detections of fall armyworm

fall army worm

There have been further detections of the exotic moth pest fall armyworm (Spodoptera frugiperda) in northern Queensland. This follows detections on the Torres Strait Islands of Sabai and Erub, Bamaga in Cape York, and in Georgetown.

Suspect moths that were collected at South Johnstone, Tolga and Lakeland were confirmed by entomologists at the Department of Agriculture and Fisheries (DAF) to be fall armyworm.

There were no detections made in the traps located at Mossman, Port Douglas, Cairns and Mareeba.

The national Consultative Committee on Emergency Plant Pests has determined that it is not technically feasible to eradicate fall armyworm from Australia.

Fall armyworm is an invasive pest that feeds on more than 350 plant species, including maize, cotton, rice, sorghum, sugarcane, wheat, and many vegetable, fruit and ornamental crops. The pest has caused significant economic losses overseas.

Fall armyworm is native to tropical and subtropical regions of the Americas, and since 2016 has spread to Africa, the Indian subcontinent, China and South East Asia.

Adult moths range from 32-40 mm in length (wing to tip). They are highly mobile and can fly long distances. Reproduction rates are high, with several generations per year.

Adult moths are nocturnal and are most active during warm, humid evenings. The larvae are caterpillar-like, light in colour with a larger, darker head. As they develop, they become browner with white lengthwise stripes and dark spots with spines.

Larvae are most active during late summer and early autumn months, however they can be active all year-round in tropical areas.

Pupae are a shiny brown cocoon formed in soil or in plant debris. The eggs are pale yellow in colour and clustered together in a mass, containing 100-200 eggs. Egg masses are usually attached to foliage in a mound with a silk-like furry substance.

Fall armyworm can be confused with a number of armyworm species that are present in Australia. However, fall armyworm is very different in terms of its impact. Distinguishing fall armyworm from similar looking moths or caterpillars requires specialist diagnosis.

The adult moth can fly long distances and is aided by wind currents. All life stages can be moved on infested plant material.

The larvae attack leaves, shoots, stems, trunk and fruit. Plants of different ages, from seedlings to mature plants, can be affected.

Fall armyworm can cause sudden crop damage and collapse, in some cases within 24 hours.

Australia’s climate and the production of suitable hosts are favourable for fall armyworm to establish and spread. Australia’s environment and native flora may also be impacted. Crops should be monitored for signs of leaf damage such as pinholes, windowing, tattered leaf margins, skeletisation and defoliation of plants.

Growers should also look out for tiny larvae, less than 1 mm, that are more active at night, eating pin holes and transparent windows in leaves and bigger larvae grazing on leaves, stems, trunk and fruit, and leaving behind excrement.

More information is available at farmbiosecurity.com.au or biosecurity.qld.gov.au.

Anyone who comes across fall armyworm is strongly encouraged to photograph and report suspected sightings to the Exotic Plant Pest Hotline on 1800 084 881. This will put you in touch with your department of primary industries or agriculture. To contact the Queensland Department of Agriculture and Fisheries, please call 13 25 23.

Source: The Front Line