Potential impact of fall armyworm on melon crops

Fall armyworm has a strong preference for maize, sweet corn, sorghum, rice and grass crops.

Melon crops, including watermelon, honeydew melon and rockmelon, are considered host crops of fall armyworm.

The potential for damage to melon crops under a field growing situation is unclear. It is possible that under high fall armyworm pressure, melons may suffer defoliation and superficial feeding on developing fruits.

Cover crops used in melon farms such as sorghum, corn and some tropical and subtropical grasses are preferred hosts.

Overseas, fall armyworm has rapidly developed resistance to insecticides where subjected to repeated and prolonged use.

What to look for

Look for egg masses, and small and large larvae. Leaf damage can be pinholes, windowing, tattered leaf margins or defoliation of leaves.

Fall armyworm damage may be confused with damage caused by cucumber moth larvae, other caterpillars and armyworm species.

There are already species of armyworm that look similar to fall armyworm present in Australia. Correct identification is important in determining the risk and response.

How to manage an outbreak

Early detection is essential. Regularly check your crops in the field for egg masses, larvae and damage. Young seedlings in trays should be checked for larvae and egg masses before they are transplanted in the field.

Key to the control of any pest is an integrated pest management approach. The Department, in collaboration with industry, is working to identify strategies and tactics for the medium to long-term response.

Some insecticides used for the control of Helicoverpa armigera, cucumber moth, other armyworms, and caterpillar pests may provide some level of control of fall armyworm. Biocontrol agents released for Helicoverpa are also expected to have an impact on fall armyworm.

Overseas, fall armyworm populations have developed resistance to insecticides when similar groups of chemistries are frequently sprayed in crops. It is essential to consider the potential impact of insecticides on natural enemies and the implications for development of chemical resistance when developing spray programs.

The APVMA is currently assessing, as a priority, applications for permits for the use of a suite of chemicals against fall armyworm in crops. Check for the latest chemical permits applying to fall armyworm by using the APVMAs permit portal—search for 'fall armyworm' and tick the 'pest/purpose' button.

You should already have strong on-farm biosecurity measures to protect your crops from pest and diseases and should implement good farm hygiene for weed control to remove hosts that could build populations.

Be on the lookout and if you suspect fall armyworm, report it immediately by phoning 13 25 23.

Further information

Read the melon fall armyworm fact sheet.