Biosecurity Alert - Serpentine Leafminer


Serpentine leafminer (Liriomyza huidobrensis) is an insect pest that is exotic to Australia which has now been detected in NSW.

This insect pest is a serious threat to a wide range of industries including vegetable crops including beans, cabbage, capsicum, celery, chilli, cucumber, eggplant, lettuce, onions, peas, potatoes and tomatoes. A number of ornamental plants including cut flowers such as chrysanthemums and gerberas are also known to host serpentine leafminer.

The pest was first detected in NSW on 22 October 2020 in Western Sydney. On 28 October, the identity of the pest was confirmed to as serpentine leafminer. During November 2020, subsequent detections were made in the broader Sydney area, Orange and the Central Coast of NSW, as well as the Fassifern Valley in Queensland.

Early detection is vital to minimising the spread and impacts of serpentine leafminer in NSW.


The patterns created in the surface of infested leaves are more easily identified than the insect itself. Look for the following signs of serpentine leafminer damage:

  • Twisting trails that appear whitish on the surface of the leaf
  • Trails that become longer and wider as the larva grows
  • Heavily mined leaves may also show large whitish blotches.

Serpentine leafminer larvae are yellow to white in colour but are often concealed beneath the leaf surface.

Adult serpentine leafminers present as tiny flies. Flies are less than 3 mm long and grey-black with yellow markings. Adult flies are not possible distinguish from other Liriomyza flies in the field and will need to be sent to NSW DPI for identification.

For more information visit the DPI website.


Part 3 of the Biosecurity Act 2015 describes how people have a General Biosecurity Duty to prevent, eliminate or minimise the risk of serpentine leafminer in NSW. People dealing with serpentine leafminer host plants which have visible signs of leaf miner damage must act to ensure they are meeting this General Biosecurity Duty. Put simply, you must always act to prevent further spread of serpentine leafminer in NSW, eliminate heavy infestations of the pest and minimise the impacts of serpentine leafminer in plant production systems.


If you suspect serpentine leafminer you must report it immediately to NSW DPI.

Serpentine leafminer is a notifiable plant pest in NSW. All notifiable plant pests and diseases must be reported within one working day.

You can report notifiable plant pests and diseases by one of the following methods:

A full list of notifiable plant pests and diseases can be found in Schedule 2 of the NSW Biosecurity Act 2015.


Find out more about plant, pests and diseases here.