Wylie says while there are quarantine checks on garlic brought into Australia for farmers to grow, bulbs brought in for people to eat are not considered to be viable.
"But they are viable and people do pop them in the garden," he says, adding that gamma radiation treatment used to stop sprouting doesn't necessarily work.
He says once a clove of imported garlic infected with an exotic virus is planted this establishes the new virus in the country.
"Then an aphid or some sort of insect that can spread that virus can land on there, acquire the virus and then fly over the fence and infect something else."
While the plant viruses don't affect humans they can hit the local garlic industry, says Wylie.
"Infected bulbs grow so much slower. They are smaller, the quality is lower and the grower gets a lower price."
In addition, he says, native orchids can be infected by some of the viruses that infect garlic.
Wylie says the study has broader implications because exotic viruses could be brought in with imported potatoes and sweet potatoes and anything else that propagates vegetatively.
"I think it's a huge problem," he says.
He says viruses also accumulate on flower bulbs so imported daffodils, tulips and gladioli may also carry viruses not picked up by current checks.
Wylie says the high-throughput sequencing technology used in the study could be used to detect viruses, even those currently unknown to science, on both exported as well as imported produce.