The Harcourt Valley Fruit Fly Action Group's Terry Willis says this could be the summer Queensland fruit fly gets a hold in the region after years of close shaves.

"If we can get through this year (by getting) on top of the fruit fly cropping up now ... then it will be very important going forward to have some sort of public knowledge about sharing fruit from infected areas," he said.

But it worth going further and setting up a fruit exclusion zone to stop people unknowingly bringing fruit fly larvae into the area?

That is an idea Mr Willis says members of the public often raise.

"They bring up the fruit bins you used to have at exclusion zone borders up every single time," he said.

"Older people in particular mention that."

More stories:

It is unclear whether fruit fly infestations the Mount Alexander Shire council reported last week in Castlemaine, Harcourt and Harcourt North can be traced back to fruit being transported in from other areas.

Mr Willis said it was possible for a small population to go undetected for some time.

However, it is clear that one of the best ways for the pest to spread is through people's garden produce.

Bendigo's proximity to Mount Alexander Shire and the close ties people in both areas have through family, friends increase the chances of fruit fly spreading.

"Maybe, going forward, we can't share fruit like we used to," Mr Willis said.

A "pest free area" remains in place in another major Victorian fruit growing region, Greater Sunraysia.

State authorities believe that area remains free of Queensland fruit fly.

The rest of the state is not so lucky.

Authorities new regard the pest as established through the rest of the state, though people like Mr Willis say some areas have less of a problem than others.

The current thinking is that roadside bins - or the checkpoints that some people may remember from Australia's past - do not work once pests establish themselves in an area.

The Harcourt action group has wondered whether it is worth doing something else often used in fruit exclusion zones: setting up signs alerting people to the dangers of fruit from outside the region.

"How we would go about doing that is another question, at the moment," Mr Willis said, noting that volunteers had been kept busy with community education, distributing fly traps and cutting down fruit trees next to public roads.

Many of the state and councils' fruit fly pushes over the last five years have focused on community education.

After all, one unmanaged tree in someone's garden can produce hundreds of flies.

Efforts have included state grants for community groups and councils to help regions raise awareness on ways to control fruit fly, announced last July.

Agriculture Victoria gave the Harcourt Valley Landcare Group a grant in 2018 to develop a plan to combat the pest.

Below: a council-commissioned community service video featuring Earnie the fruit fly.

Both Mount Alexander and Greater Bendigo's councils have produced community service videos starring Ernie the cartoon fruit fly, who is "here to wreck your garden".

Agriculture Victoria's statewide fruit fly coordinator Cathy Mansfield reinforced that message in comments to the Bendigo Advertiser for this story.

"With the current La Nina weather pattern, we are more likely to see higher populations of Queensland fruit fly this summer than in recent years," she said.

More on fruit fly threat: 'Do something now - or eat maggots': saving central Victorian fruit one tree at a time