Locust swarms causing havoc

Warm weather across Victoria this week could worsen a locust plague already threatening to become the state's worst in 75 years.

The highest density swarms - more than 50 locusts per cubic metre - have been sighted around Echuca in northern Victoria as they head south.

Swarms have also been reported across central Victoria, but the Victorian Farmers Federation (VFF) says they are not posing a serious threat to crops.

Department of Primary Industries (DPI) state locust director Rob Walker said warm weather will provide favourable conditions for the locusts to breed across most of Victoria.

But forecast rain could stop the locusts swarming, he said.

Mr Walker said the movement of locust swarms was unpredictable, but swarms varying from low to high density have been reported from areas along the Murray River and south of Swan Hill.

"Low to medium density swarms have been reported around Bendigo, Donald, Murchison, Ouyen, Rochester, Kerang, Marungi, Charlton and Seymour in the state's north and central areas," he said in a statement.

"DPI field crews and entomologists have also confirmed reports of adult locusts laying eggs in the Seymour area (100km north of Melbourne).

"Another generation of locusts can hatch as early as 10 days after egg laying if the weather conditions are favourable.

"This means it is crucial for all landholders to report any egg laying activity on their properties."

The DPI's locust swarm activity map shows locusts have been seen on Melbourne's outskirts in Sunbury and Epping.

Callers to Fairfax Radio on Monday reported seeing locusts even closer to Melbourne's CBD in Yarraville.

Mr Walker said the DPI was spraying locusts in north-west and north-central Victoria and urged farmers to do so too before they reached adulthood and take to the air.

VFF president Andrew Broad said the locusts were not affecting grain harvests and did not pose a threat to a large number of crops.

The swarms were an inconvenience to dryland lucerne and some horticultural crops as well as people`s gardens, Mr Broad said.