An aggressive microscopic pest that stunts plants and causes galls on sweet potatoes has been found in Australia for the first time.
The Northern Territory's chief plant health officer has confirmed guava root-knot nematode was detected on four properties in Middle Point, Jingili, Palmerston and Malak.
The nematode was found on sweet potato, cucumber, capsicum, butternut pumpkin, snake bean, zucchini and chilli plants at a commercial farm, two residential gardens and a community garden.
How and exactly when it came to the Northern Territory was a mystery.
"We've started doing some work around tracing, and at the moment we can't find a link between the properties," Chief Plant Health Officer Anne Walters said.
"We had a sample from 2021, we thought it was a different type, and when we went back and tested it, we found it was this species.
"So it has been in the Northern Territory for at least 12 months."
The roundworm affects the crop yield of several vegetables, fruit and agricultural fibres such as cotton.
"It really likes sweet potato, it's the number one pest for sweet potatoes," Dr Walters said.
Slim chance of eradication
Dr Walters said it was a serious concern nationally and it would be difficult to remove from the Northern Territory.
"It's very widespread which means the likelihood of eradication is quite low, however the likelihood of it moving from the NT is low because we don't trade in a lot of the goods nationally it is found in.
"The issue is that it can move in soil.
"We are asking growers to submit any samples they might be concerned about.
"The difficulty with this particular pest is that unfortunately you actually don't see any symptoms until the plants start to fail."
The pest is invisible to the eye and has previously been found in regions with tropical climates, around Asia, Africa, Europe, South and Central America.
The Department of Tourism Industry and Trade has asked for people to identify symptoms including stunted growth, wilting, yellow leaves and deformed roots and contact the plant biosecurity team.
