Guava root-knot nematode

Guava root-knot nematode is an aggressive round worm disease.

It affects the crop yield of several vegetables, fruit and agricultural fibres.

Its scientific name is Meloidogyne enterolobii.

Where it is found

Guava root-knot nematode has been detected in 4 premises in Middle Point, Jingili, Palmerston and Malak.

It was found on:

  • sweet potato
  • cucumber
  • capsicum
  • butternut pumpkin
  • snake bean
  • zucchini
  • chilli plants.

There are no known tracing links between the infected properties.


Guava root-knot nematode is similar to other species of root-knot nematode.

All life stages are microscopic and require magnification to be seen.

Second stage juveniles are translucent and vermiform (worm-shaped), with a tapered tail and rounded head with a delicate stylet.

Females are white, pear-shaped with projecting necks tapering to the head, and can vary in size.

Males are translucent, vermiform (worm-shaped), with a rounded head and blunt, rounded tail. They’re much larger than juveniles with a more robust stylet and head framework.


Guava root-knot nematode causes severe knotting of a plant’s root system.

It can cause stunted growth, wilting and the yellowing of leaves.


Guava root-knot nematode spreads through the soil attached to machinery, tools, footwear, and plant products.


To protect your farm or property, you should:

  • buy planting material from reliable suppliers and request a written statement demonstrating the absence of plant-parasitic nematodes
  • ensure planting material is free from soil and plant residues
  • keep records of where plants, planting material and tubers:
    • are sourced from
    • where and when they’re planted on your property
  • check planting material on arrival to make sure they’re free of all pest and disease symptoms
  • regularly check your farm and report any unusual or unfamiliar symptoms or damage to plants.

How to report

If you think you have seen guava root-knot nematode in the NT:

Submit a sample

You can submit a specimen for identification to the Department of Industry, Tourism and Trade (DITT).

To find out how to submit a sample go to the DITT website.

More information

For biosecurity alerts and updates, go to the Biosecurity NT Facebook page.

Last updated: 16 November 2022

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