A chance discovery of a ladybird "possibly carried in on a cyclone" may be the answer to controlling destructive pests that cause millions of dollars of damage each year to tomato and potato crops.

Key points: The foreign grey ladybird, or Olla v-nigrum, was found in Queensland's Bowen and eats problem pest psyllids

The foreign grey ladybird, or Olla v-nigrum, was found in Queensland's Bowen and eats problem pest psyllids Introduced into nearby New Caledonia, an agronomist says it may have arrived in Australia on the winds of a cyclone

Introduced into nearby New Caledonia, an agronomist says it may have arrived in Australia on the winds of a cyclone Predatory spotted ladybirds had been used for many years as an effective aphid control

The grey ladybird was found preying on tiny sap-sucking insects called psyllids in a leucaena crop on a farm near Bowen in north Queensland, where it attracted the attention of local agronomist Chris Monsour.

Never having seen a grey ladybird before, he investigated further and found the predatory insect well established in the pasture crop.

"They eat psyllids, which are problem pests in leucaena, but we have psyllids that are pests in other crops including a recent tomato potato psyllid," Mr Monsour said.

Tomato potato psyllid nymphs on the underside of a tomato leaf. ( Supplied: WA Agriculture Authority/DAFWA )

"The thinking is that this particular ladybird may have a preference for psyllids so we're starting to look at rearing the insect to see if it will eat other pest psyllids as well."

The tomato potato psyllid, first detected in Western Australia, is predicted to eventually reach the eastern seaboard and is a serious threat to solanaceous crops such as capsicums, tomatoes and eggplant.

"If established it could move very quickly and potentially have a significant impact on horticulture," Mr Monsour said.

"There's a lot of agricultural crops up and down the eastern coastline. If established, it could potentially have a significant impact.

"What we're trying to do up and down the east coast is to make sure we are being vigilant looking for it so it can be detected early and managed."

'Wizard of Oz-style' arrival to Australia?

Ladybird expert Adam Slipinski from the CSIRO said it was not known where the ladybird had originated from.

The grey ladybird species is called Olla v-nigrum and is native to North and Central America.

It has been introduced to Hawaii and New Caledonia.

"This was my surprise to know that there is a large population of this species near Bowen and have no idea how it was established and what is the origin," Mr Slipinski said in a statement.

"We can probably investigate that using DNA to see if our population is more closely related to the Pacific populations than to the US. That would be my guess."

Mr Monsour said a few theories as to how the ladybird arrived had been contemplated.

"There is a possibility it was carried from New Caledonia on wind currents, and more than likely with cyclones, and was somehow just deposited in this region," Mr Monsour said.

"It's well known insects do disperse on wind currents, and some of them can travel huge distances.

"Most insects will use currents that are traditional wind directions. But in cyclones they might not have had an opportunity to decide what was going to happen, and just be picked up and dumped — Wizard of Oz-style."

Breeding program begins

Ladybirds have been sent to breeding facilities for testing to see whether they could become biological control agents and be mass-released at psyllid infestation sites to devour the pests.

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Entomologist Dan Papacek from Bugs for Bugs, a Mundubbera-based biological control agency, said predatory spotted ladybirds had been used for many years as an effective aphid control.

With increased pest incursions throughout Australia as a result of expanding trade and people movement, Mr Papacek said the possibility of new tools in the fight against psyllids showed promise.

"The idea is to reduce the reliance on pesticides. It's not a new concept but it's certainly one that's gaining momentum in the last two or three years, or maybe a little bit longer," he said.

"We are seeing a lot of elevated interest in what we do in providing alternatives to pesticides and I think everybody's starting to realise there are a lot of negatives associated with pesticide use.

It is not yet known where the beetle came from, but it may have arrived from the Pacific with a cyclone. ( Supplied: Prospect Agriculture )

"Things like residues in food and resistance. Insects are very adept at developing resistance to a lot of these products. Also conserving what are quite valuable agricultural tools for the future."

Before the grey ladybird can be sold commercially on the market, stringent testing must occur to make sure the insects would not cause wider problems in the ecosystem.

It is something Mr Papacek said he believed was unlikely.

"Though they're capable of grazing, if you like, on alternative hosts, they're generally very specialised," he said.

"My suspicion, just from what I know, is that the risk is probably quite low."

Hopeful of a control

Despite optimism in the sector, the ladybird would not be a magic bullet to the tomato potato psyllid issue, which is just one of the hundreds of biosecurity threats Australia faces as borders become increasingly fluid in the modern age.

It is feared that the tomato potato psyllid could eventually cross into eastern Australia imperilling the nation's $3.5 billion vegetable sector. ( Supplied: DAFWA )

Shaun Lindhe of the national horticulture lobby group Ausveg said research on controlling the sap-sucking bug had begun in WA in the form of glasshouse trials of insecticides and biocontrols.

But he urged caution.

"Biological control options have the potential to be used in conjunction with a range of other control options, including integrated pest management practices," he said.

"As a winged insect, it can travel on wind currents and on clothing, produce and other means of transport.

"It is essential that growers, industry members and the general public follow strict biosecurity measures to limit the spread of harmful pests and diseases."