WIMMERA and Mallee grain growers will be hit with a double whammy of locusts and mice this spring, potentially costing Victoria more than $2 billion.

But it's no coincidence both pest populations have reached plague proportions in the same season in some regions of northwest Victoria.

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  • Pests to cop quite a spray

Ideal weather conditions - moderate temperatures, rain and food availability - have created the perfect storm, scientists say.

Failure to manage locusts alone could cost Victoria $2 billion in lost production, while not baiting for mice could result in losses of $100 million the experts have warned.

Australian Plague Locust Commission director Chris Adriaansen said there "was nothing anyone can do to prevent the fact there will be (locust) swarms at the end of the spring and they will breed again".

He said farmers needed to carefully monitor the situation with an approach to population management, rather than eradication.

But while numbers grow, scientists are hatching a plan of their own to turn the locust on itself.

Associate Professor Greg Sword from the University of Sydney said locusts were cannibals that moved in search of food and to escape becoming a meal themselves.

"If you could influence the genes that cause them to respond to other insects and move away (and) reduce their movement, you would increase the incidence of cannibalism within the group," Prof Sword said.

"The locusts would effectively be feeding on themselves and could help limit their own populations."

The concept was based on the understanding that much of the frenetic activity in a swarm was a direct consequence of insects trying to eat others and avoid being eaten themselves, he said.

Meanwhile, mouse plagues have increased from once every 10 years to once every four years.

Dr Mathew Crowther, also from the University of Sydney, said good rain without excessive temperatures had created ideal breeding conditions for mice.

Availability of high-quality feed had shortened the time taken to reach maturity, increased fertility and improved breeding efficiency, he said, leading to the population to grow from 50 a hectare to 3000 a hectare.