Australia's latest plant pest invader was hiding here for a year or longer

Meloidogyne enterolobii, or the Guava Root-Knot Nematode, has already spread in the Northern Territory with fears it may have been here for a year or more before being discovered.

The microscopic animal is officially listed as a high priority pest for the ginger, onion, papaya, potatoes, vegetables (tomatoes) and sweet potato industries.

It is also a danger to lucerne, tobacco, cabbages, wheat and corn.

It has for years been identified as affecting plant crops to our north.

NT officials say it has already been determined the pest will be difficult to eradicate.

Those officials are already dealing with several outbreaks including the unwanted reemergence of banana freckle.

National emergency response arrangements means it must be determined whether the discovery is defined as an "emergency plant pest" and whether it is technically feasible to eradicate.

For now the focus is again on the NT where plant biosecurity staff are working with the local growers with infected plants to prevent a wider infestation.

It has been confirmed at properties in Darwin and Palmerston.

Nematode juveniles are thread-like worms about 0.5mm long, too small to be seen with the naked eye.

The pest was found on sweet potato, cucumber, capsicum, butternut pumpkin, snake bean, zucchini and chilli plants.

Guava Root-Knot Nematode was confirmed after a sample of cucumber roots taken from a farm was analysed by plant biosecurity staff.

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Further investigations by biosecurity staff suggest it may have been present in the Darwin area for 12 months.

Government officials are now "assessing movement pathways" to learn if the pest has spread from the NT to other jurisdictions.

It spreads through soil attached to machinery, tools, footwear, and plant products.

NT chief plant health officer Dr Anne Walters said plants affected by the latest invader exhibit stunted growth, wilting and yellow leaves.

"... work can begin to assess how far the pest has spread and a plan can be formulated with industry on how to best progress with activities from here."

Northern Australia has long been identified as being vulnerable to incursions of exotic plants, bugs and diseases through its proximity to adjacent countries.

Officials are on high alert for livestock diseases like African swine fever, lumpy skin disease and foot and mouth disease.

The dog killer ehrlichiosis was first detected in the Kimberley in May 2020 and quickly spread around Australia.

Fall armyworm reached the Australian mainland in the north in early 2020 and has since spread across much of northern and eastern Australia.

Japanese encephalitis is now believed to have arrived in Australia a year earlier than first thought after a person in the Tiwi Islands, offshore from Darwin, died from the disease in early 2021.

The nation was only alerted to the arrival of JEV in late February this year when the virus had already taken hold in piggeries in Victoria, Queensland and New South Wales.

That JEV outbreak has already caused 40 cases of human infection and led to five deaths with fears of the dangers for many more cases as a result of the spring floods.