Charles Sturt University Professor of Applied Ecology Geoff Gurr said the diamondback moth is a common pest in vegetable gardens and farms.

"The caterpillars feed on brassica flowers and leaves, like cabbage, broccoli, brussel sprouts and canola, costing more than $5 billion world-wide in lost production and control costs," he said.

"We have discovered the diamondback moth originated in South America, and started moving about 500 years ago, initially through Central and North America before invading Europe, Asia and finally the Pacific.

"Initially, researchers theorised the moth originated from the Mediterranean or China, but the research has found it was actually from South America."

The study was led by Fujian Agriculture and Forestry University in China where Professor Gurr was a visiting professor.

He also said Australia has a 'young' population of the diamondback moth but it has adapted to feeding on native brassica weeds and other important crops and researchers will be able to look for natural agents to control the moth.

"The specimen used its adaptive capacity to cope with the new climates and plants it encountered," Professor Gurr said.

"The global expansion of agriculture, including the brassica plants, has fuelled growth of populations sizes.

"We are looking to find a parasitic wasp to control the moth but we have to ensure it is beneficial to the environment as there are multiple species."

Professor Gurr also said this study sets a precedent for future genetic research on flora and fauna .

"This study provides a foundation for different types of specimens, understand their genetic structure and provide resources for biosecurity risks," he said.