News

Fall armyworm (Spodoptera frugiperda) is an exotic pest that has been detected in Queensland and poses a threat to Queensland's agricultural industries. Since April 2020, the exotic pest has been detected in Bundaberg, which is the most southerly since the initial detection in the Torres Strait islands in January 2020.This is not unexpected as fall armyworm is highly mobile. Even though macadamia are unlikely to be affected by this pest, grower vigilance is required.

Fall armyworm is reported to feed on more than 350 plant species, including maize, cotton, rice, sorghum, sugarcane, wheat, and vegetable and fruit crops, and have caused significant economic losses overseas. Destruction of crops can happen rapidly when infestation levels are high. While this pest is native to tropical and subtropical regions of the Americas, since 2016 it has rapidly spread to and throughout Africa, the Indian subcontinent, China and Southeast Asia.

Fall armyworm includes two subpopulations, or strains and can be confused with a number of armyworm species that are present in Australia.

Description

Adults

• Moth, 15–20mm with a 32–40mm wingspan.
• Brown or grey forewing and a white hind wing.
• Male fall armyworm moths have more patterns and a distinct white spot on each forewing.

Larvae

• When larvae are newly hatched they are about 1.7mm, light green to brown with a larger, darker head.
• As they develop, they become a darker greyish-brown with white lengthwise stripes and dark spots with spines on their upper surface, with a pale underside. Older larvae have a distinctive pattern of 4 spots on the second to last body segment and an inverted 'Y' shape pattern on their heads.
• Eventually reach a length of about 34mm.

Plant damage

Fall armyworm larvae initially feed on leaves, creating pinholes and windows in leaf tissue, and giving leaf margins a tattered appearance. In grass-like plants, they often feed within the leaf whorl (where leaves radiate from or wrap around the stem or stalk—see image 2 below). Insect frass (droppings) is a sign that larvae are present.

Fall armyworm larvae can also eat buds and tunnel into and feed on fruit. Larger larvae can cut plants off at the base.

Many larvae may be present on one plant. When they are found in large numbers, they can defoliate preferred host plants and acquire an 'armyworm' habit and disperse in large numbers. Crops have been reportedly been destroyed almost overnight.

Impacts

Damage caused by fall armyworm can reduce plant growth, significantly reduce crop yield and cause plant death. Severe infestations can destroy crops rapidly.

Since fall armyworm can also graze on some pasture species, our environment may also be impacted.

Identification & reporting

Identification & symptom resources are available at https://www.publications.qld.gov.au/dataset/queensland-fall-armyworm-resources

If you suspect fall armyworm, report immediately to the Queensland Department of Agriculture and Fisheries on 13 25 23.

Permits

Three emergency permits are in place for the control of fall armyworm in macadamia, should the pest be detected.