Swarms of locusts are now predicted to form in northern NSW this month, according to the latest Australian Plague Locust Commission bulletin.

Victoria and SA are expected to see locust swarms from late November and continuing into summer if many locust “nymphs” survive the spring.

The bulletin says locust nymphs have been hatching across NSW, Victoria and SA for several weeks, although no major infestation has been reported in Queensland.

“Hatchings will continue in October, and widespread high density nymphs are expected to develop in these areas and in the NSW Riverina and north-central Victoria,” the bulletin says.

The commission is warning the survival of many nymphs could lead to localised damage to cereal and other crops in many of the affected regions if spraying fails to reduce the populations.

In Queensland, heavy rainfall and green vegetation is producing perfect conditions for the resident adult population of locusts to breed during the next couple of months, the bulletin says. This will create a significant population of adult locusts next year.