The larval stage of the fall armyworm (Spodoptera frugiperda) is a pest that can damage and destroy a wide variety of crops causing large economic loss. Outbreaks of the true armyworm usually occur during the early part of the summer.
The adult moths are 32 to 40 mm wing tip to wing tip, with a brown or grey forewing, and a white hind wing. Male fall armyworms have more patterns and a distinct white spot on each of their forewings. During the development stage, the larva is light colored with a larger dark head. As they develop, they become browner with white lengthwise lines. They also develop dark spots with spines.
Adults are capable of flying long distances. Their migration rate is remarkably fast, estimated at almost 500 kilometres per generation. They can also spread through people movement, with it believed that their arrival in Africa was on via a passenger flight.
The fall armyworm has not been reported in Australia. It is native to tropical to sub-tropical areas of America. Initial detection in Africa in 2016 saw the fall armyworm spread to more than 30 countries over 3 years. In 2018, for the first time, the fall armyworm was detected in India and Sri Lanka. In 2019 it has spread to Asian countries including; Bangladesh, Thailand, Myanmar, China and Indonesia. A suitable climate, trade and transport routes mean Australia could potentially face a high threat of fall armyworm invasions originating from neighbouring and trading countries.
The fall armyworm larva is known to eat more than 180 plant species, many of which are relied upon by humans.
Destruction of crops can happen almost overnight, because the first stages of a larva’s life require very little food, and the later stages require about 50 times more. Because of this rapid change in food consumption, the presence of larva will not be noticed until they have destroyed almost everything in as little as a night.
Examples of targeted crops include cotton, tobacco, sweet corn, rice, peanuts, and fruits including apples, oranges, and many more. The list of possible food sources for the larvae is extensive. Because the larva eat so much of the plant, they are extremely detrimental to crop survival and yield.
If you suspect fall armyworm, you should immediately call the Exotic Plant Pest Hotline on 1800 084 881 or email email@example.com with a clear photo and your contact details.