Reports of fall armyworm infestations in a specific type of grazing oat across Queensland’s southern growing regions has prompted an immediate warning for graziers to check their crops.
The Department of Agriculture and Fisheries issued the warning after the invasive insect had reportedly been found infesting forage oats in regions including the inner Darling Downs, Southern Downs, Western Downs and Rolleston in Central Queensland.
Forage oats are the preferred winter grazing crop for beef and dairy cattle in Queensland, due to its ability to produce good quality feed when most pastures are dormant.
The Department’s Principal Entomologist Dr Melina Miles said emerging and establishing crops were “at greatest risk of complete defoliation and plant death”.
“Growers and agronomists are encouraged to check crops for evidence of fall armyworm within seven to 10 days of emergence,” Dr Miles said.
“In oat–pasture mixes you may see damage to grasses and broadleaf pasture species when the FAW have consumed the oats and move as larger larvae.”
The infestations follow the end of the most damaging season of fall armyworm incursions since the invasive insect arrived in the country in 2020.
If Queensland experiences a mild autumn, the insect’s activity in winter crops and pastures is expected to persist, but the rate of damage will slow as average temperatures decline, according to the Department of Agriculture.
Departmental advice suggests emerging and establishing crops “are at greatest risk of complete defoliation and plant death.
DAF advice for graziers:
Crop-checking intervals of seven to 10 days will avoid damaging infestations going undetected.
Look for windows or holes in leaves where small larvae have fed, or evidence of more substantial feeding with tillers cut off and plants completely eaten.
Bare patches in the paddocks and dying plants are indicative of more severe infestations.
Don’t rely just on finding damage – pull up damaged plants and confirm the presence of larvae (caterpillars).
Medium and large larvae may shelter under the soil surface at the base of plants during the day.
Carefully inspect the soil around the base of damaged plants. Damage to stems by these larger larvae can result in plant death from dehydration or disease.
Once larvae are 20mm long they will cause significant damage in a short period of time. Timely detection is crucial to minimise losses and safeguard yields.
If fall armyworm is detected, growers should seek support from their local agronomist.
