FALL armyworm moths and larvae were yesterday (October 15) detected in traps east of Narrabri and west of Moree.
Growers and consultants in the North are urged to check summer crops for damage.
After an initial detection of a single male moth in a pheromone trap between Moree and Boggabilla on September 23, more moths have been collected from traps east of Narrabri and west of Wee Waa on October 12 and 15.
The latest detection of the moths prompted trap collaborators to inspect an adjacent corn crop, where they almost immediately found symptoms of damage, and located small fall armyworm larvae.
Early symptoms include 'windowing' of leaves, where larvae have hatched, and small 'shot holes' in leaves as they expand, from larvae feeding within the leaf whorl before it has expanded.
Identification of recently-emerged larvae can be difficult in the field, but by the time the larvae reach second to third instar the features that allow diagnosis are more obvious.
For small larvae, the Department of Primary Industries and Local Land Services recommend retaining samples with food, such as host crop leaves, and allow them to grow to enable photographs to be taken.
In most cases DPI will be able to provide a diagnosis from clear photographs.
Images of suspect fall armyworm can be sent to the NSW DPI biosecurity for assistance with identification.
Anyone who suspects the presence of fall armyworm should immediately call the exotic plant pest hotline on 1800 084 881.
Growers can email email@example.com with a clear photo and include contact details.
Fast action to control larvae while they are small is recommended to maximise efficacy, to help restrict local population increase and to minimise further spread, said a DPI spokesman.
"If a decision to treat a crop is taken, we recommend retaining samples of larvae before the treatment is made, which will help with becoming familiar with life stages and may be important if treatments are not considered effective," he said.
"Careful consideration needs to be given to product choice, as genetic testing has indicated that fall armyworm sampled from northern populations carry markers for target site resistance associated with organophosphate and carbamate chemistries.
Growers and consultants are encouraged to access the NSW DPI and LLS websites fall armyworm pages for information about identification, treatment options and resistance management.
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