Biosecurity Tasmania (BT) is investigating a detection of serpentine leafminer (Liriomyza huidobrensis; SLM) at a commercial grower site in North West Tasmania. SLM is a high-risk invasive pest of horticulture and vegetable production systems and is exotic to Tasmania.
What we know
This is the first confirmed detection of SLM in Tasmania. SLM has been present on mainland Australia since 2020 and is considered established in New South Wales, Queensland and Victoria.
The detection came after a concerned grower reported unusual insect activity on host plants to BT. Initial diagnostics indicated that the sample was likely SLM, with a high degree of confidence. Molecular testing results confirmed SLM on 23 June 2026.
It is not currently known how or when SLM entered Tasmania, or whether there are any other populations here.
SLM is classed as Prohibited Matter in Tasmania under the Biosecurity Act 2019.
BT undertook a rapid risk analysis when SLM was first detected in NSW. The analysis concluded that treatment options were not practical or cost-effective at the time, so there are no SLM specific import requirements for hosts entering Tasmania.
What we’re doing
BT is working with the impacted grower to manage the detection, with site-specific biosecurity directions in place to control and minimise spread.
BT is also investigating potential movements, including trace back/forward of stock to better understand the potential distribution of the pest.
BT will work with affected Tasmanian industries to understand and determine actions to be taken following this detection.
What is serpentine leafminer?
SLM is a leafmining fly in the genus Liriomyza that is exotic to Tasmania.
The larvae of this group of flies cause damage to plants by tunnelling through the leaves as they feed – these tunnels cause visible damage known as ‘mines’. High level of infestations can reduce plant growth and yields.
SLM and other exotic Liriomyza flies are a threat to Australian agriculture as they are known pests to over 200 different plant species, including crops such as potato, beans, peas, brassicas, lettuce, celery, tomato and cucurbits. They may also impact ornamental plants such as chrysanthemum, gypsophila, ranunculus and other nursery plants. Numerous weed species can act as reservoir hosts, allowing populations to persist between crop cycles.
Leafminers similar to SLM are very common in Tasmania and entomologists can only make an accurate diagnosis can only be made by rearing larvae through to the adult stage or using molecular testing.
Common leafminers in Tasmania include L. chenopodii (beet leafminer), L. brassicae (cabbage leafminer), Chromatomyia syngenesiae (cineraria leafminer) and Scaptomyza flava (turnip leafminer).
What you can do
Growers and members of the public should look out for distinctive squiggly white lines on plant leaf surfaces caused by feeding damage from leafminer larvae.
Due to the presence of other leafminers in Tasmania, reporting should be prioritised to the following cases:
Heavy leafminer infestations on commercially grown plants, particularly if the infested plants have not been infested previously.
Plants that are not commonly infested by leafminer species already present in Tasmania, including:
Aster sp. (e.g. daisies)
artichoke
Bellis perennis (lawn daisy)
beans
Calendula sp. (e.g. pot marigold)
carnation
celery
cucumber
coriander
Gladiolus sp.
pumpkin
Ranunculus sp. (e.g. buttercups)
squash
sunflower
Tagetes sp. (e.g. marigold)
Verbena sp.
Viola sp.
zucchini
If you see leafminer damage on these plants, or suspect possible SLM:
Restrict access to the area and don’t move any plants or plant material off-site.
Note the location and get a photo of the damage and leafminers if you can.
Report it to Biosecurity Tasmania: Phone: 1300 368 550; Email: biosecurity.tasmania@nre.tas.gov.au.
Good farm biosecurity helps to prevent the spread of pests, weeds and diseases. Remember to look out for new and/or unusual pests, weeds and diseases in crops, production areas and in high-risk inputs (e.g. mulch, fill, new planting material). Report them to Biosecurity Tasmania if you are concerned.
More information
More information, including images of SLM and SLM damage, is available on our Serpentine Leafminer page.