Management overview
The fall armyworm (Spodoptera frugiperda) is a plant pest that can damage a wide variety of crops. The larvae predominantly feed on crops and pastures from the Poaceae (grass) family, in particular maize, but also sorghum, and forage grasses. It has also been noted on other grass crops including cereals but these are considered secondary hosts. The pest can also feed on non-grass crops such as cotton, vegetables and some fruit crops. Fall armyworm is known for its ability to disperse and migrate long distances, which enables it to exploit new habitats and expand its range when favourable host plants and climatic conditions are present.
Fall armyworm management has been a challenge worldwide. The key to effective management is early detection of the pest in the crop and regular monitoring to assess the population build up.
If fall armyworm becomes an important/consistent pest in a particular region, a pheromone trap can be deployed to check on the presence of moths as a warning of potential pest situations.
Larval monitoring is a more reliable method for determination of infestation.
Host-plant resistance and variations in production practices have been used quite successfully in other parts of the world. Integrated Pest Management that employs a variety of tactics will be essential to managing fall armyworm for the long-term.
Further research is needed to understand more about this insect, how it is going to impact the crops in Western Australia and even where and when it will become problematic. Management strategies will also be an important research area for DPIRD.
For an overview on managing fall armyworm in Western Australia, see the webinar conference presentation delivered by DPIRD senior research scientist Helen Spafford on 9 April 2020 to growers, agronomists and stakeholders. Alternatively, read the PowerPoint presentation.
Special considerations
Fall armyworms will feed on crops where other lepidopteran pests, such as cluster caterpillar, armyworms, bollworms and others, are already present and established. Many of the management strategies used for lepidopteran pests may also be effective for fall armyworm.
Pesticides are often the primary tool for management and many products are effective at reducing pest numbers. However, fall armyworm is reported to relatively quickly develop resistance to insecticides and insecticide use for fall armyworm may also change the dynamics of other pests in the system. It is therefore important to use insecticides judiciously. Where required, APVMA permits should be read in conjunction with the relevant product label for information on withholding periods and other critical comments.
Natural enemies are found suppressing fall armyworm populations around the world. There is a suite of natural enemies that attack pests similar to fall armyworm in the same crops in Western Australia. It is likely these natural enemies will also reduce fall armyworm numbers. If pesticides are used for fall armyworm management, it is advised that beneficial-friendly products are applied.
The following links provide information on scrop-specific fall armyworm management options: