Fall armyworm found at St George, Chinchilla and in the Lockyer Valley

Fall armyworm has been spreading across the nation after it was first detected in January on two Torres Strait islands before it arrived on the mainland at Bamaga in February.

Department of Agriculture and Fisheries principal entomologist Dr Melina Miles said southern Queensland farmers need to be on high alert.

"Given fall armyworm was recently detected in the several parts of southern Queensland, growers should be watching both the level of activity in local traps and closely monitoring the vegetative state of their crops," Dr Miles said.

"They can work with their entomologist to identify the signs that fall armyworm are active and to distinguish them from native armyworms.

"The risk in northern NSW and central Queensland, in places like Emerald and the Darling Downs is real and growers there need to be on high alert."

Dr Miles said for sorghum growers it was important to inspect the crops during the vegetative stage and not just from head emergence, particularly if traps were indicating the pest was active to the north or west of their property.

She said there was still a lot to learn about the effects of the pest on Australian crops.

"We've not previously seen a pest that can reduce the amount of functioning leaf area to the point where it warrants control in the vegetative stage, and that is what fall armyworm is doing - particularly in maize and sweet corn," Dr Miles said.

"In the Burdekin, growers tell you that every crop of maize or sorghum they have has been affected to some extent."

DAF has been working with Pacific Seeds to help provide growers with tools to manage the pest.

This includes developing an integrated pest management strategy and simulating damage at varying crop stages to assist in refining the timing of control measures.

Pacific Seeds summer grains agronomist Trevor Philp said farmers need to be aware of the risks.

"The spread of this pest could have unknown consequences for what promises to be a strong growing season, with a La Nina event driving potentially good rainfall across Australia," Mr Philp said.

"That's why we are working closely with the department to help give growers the tools to manage this invasive pest.

"Currently we're simulating fall armyworm damage on corn to see when growers should be intervening to avoid detrimental damage.

"This is because fall armyworm damage can look worse than it is, and we don't want growers intervening with pesticides until it's necessary to do so."