Guava root-knot nematode has been detected for the first time in Australia in the Northern Territory — leaving farmers with questions about what to do next.
The pest severely impacts sweet potatoes by damaging their roots.
It also stunts the growth of a wide range of other crops, including cotton, cucumbers, capsicums, pumpkins and zucchinis.
The Northern Territory's chief plant health officer said the pest had been found in four locations in the territory and the likelihood of eradication was quite low.
So how worried should farmers be and what should they do if they find it on their property?
Fumigation used in the United States
Johan Desaeger, an associate professor from the University of Florida, said he was not surprised to hear the pest had been found in Australia.
"Australia was the last continent, except for Antarctica, where this nematode had not been reported yet," he said.
"It was first identified in the 1980s in China … but I believe this nematode has been around the tropics and sub-tropics across the world probably for millions of years."
The nematode was first detected in the United States in 2004.
Mr Desaeger, who co-authored a report on the pest this year, said the nematode liked warm weather and sweet potato farmers in the United States were using fumigation to control it.
"I don't think it's had a big impact yet in Florida where I am, although it's had an impact in North Carolina where it's been impacting the sweet potato industry — but that's more of a quarantine issue because the tubers are an ideal (host) to spread this nematode," he said.
"My advice is to keep monitoring it, keep sampling.
"I wouldn't go into panic mode, just be cautious and if you see root-knot on any crops, get it properly identified … the more information you have the better."
He said he doubted it would spread to the temperate climates of Australia.
Keep an eye out for signs
The University of Southern Queensland's Gavin Ash has been studying sweet potato pests and diseases in Australia and Papua New Guinea for the past decade.
He said root-knot nematodes were like "little tiny eels that live in the soil" and in general were one of the "highest-problem" pests for sweet potatoes.
"The problem with nematodes is they're quite insidious — they're small, you don't notice them and then all of the sudden you realise you're not getting as much yield as you used to get and your yield declines over time," he said.
"The other really important thing with sweet potato, is that any sort of damage or blemish on the potato makes it unsaleable, because people don't want to buy a potato with black marks or lumpy bits on them."
He said there was a risk the guava root-knot nematode was already in Queensland and that it was important for growers to keep and eye out for signs.
"We have other (types of) root-knot nematodes in sweet potato and they're seen as number one or number two in terms of pests and diseases on the roots, and because they're in the soil they're more difficult to manage."
Queensland farmers concerned
With the threat right on their doorstep, Queensland's sweet potato growers feel they have been left in the dark.
Wolfies Farms is a major sweet potato producer based in Rossmoya, near Rockhampton in Central Queensland.
Manager Rodney Wolfenden said he was taken by surprise by the news of the pest.
"I'm not familiar with it at all, it's not something that we've had here previously" he said.
Mr Wolfenden first heard about the pest from a fellow member of the sweet potato industry and said he was yet to receive contact from the Department of Agriculture and Fisheries.
"There has been no contact from the department, the only thing that we've seen is a press release, but essentially no information about it — nothing," he said.
Mr Wolfenden said he was unsure of his next steps.
"I'd like to think that there are attempts made to eradicate it or at least contain it — I'm pretty disappointed that it's there," he said.
"The only good thing I can see … is that it has actually been spotted and now we can do something about it."
Mr Wolfenden said it was the last thing the industry needed.
"We've been through a hard time over the last couple of years, we don't need something like this to turn up," he said.
"It's going to affect a wide range of other crops as well — no one needs that sort of thing."
Farmers urged to report suspected cases
In a statement provided to the ABC, Biosecurity Queensland urged growers in the state to remain vigilant.
"Guava root-knot nematode is a significant threat to horticultural industries as it can be more destructive than other root-knot species on many crops," it said.
"The risk of spread from the Northern Territory into Queensland and other jurisdictions for plant products and commodities currently traded is considered very low, although the risk for nursery plants is likely to be higher."
Farmers with suspected guava root-knot nematode on their property were told to report it immediately to Biosecurity Queensland on 13 25 23, online at daf.qld.gov.au or to the Exotic Plant Pest Hotline on 1800 084 881.
