PLANT PEST
Exotic leaf miner species
Exotic to Australia, one species under management in Northern Peninsula Area of Cape York
Features: Tiny insects whose larvae cause damage by tunnelling through the inside of leaves leaving a meandering track
Where they're from: North, Central America and Caribbean, South America, Europe, Africa, Asia, Oceania
How they spread: Importation of infested plants or cut flowers; pupa in soil; locally by flying
At risk: A large number of species including melons, vegetables, onions, grains, cotton, ornamentals and production nurseries
Leaf miners damage leaves by feeding inside them leaving squiggly trails.
Scot Nelson, Flickr.
Keep them out
Leaf miners are tiny greyish black flies about 2 mm long, whose larvae (grubs) feed under the surface of leaves. Feeding causes loss of healthy leaf tissue, so the plant can’t capture enough sunlight and often becomes infected with disease. Plants often fail to grow or produce crops.
While there are over 300 leaf miner species worldwide, there are five considered to be serious pests:
- Vegetable leaf miner (Liriomyza sativae)
- Tomato leaf miner (Liriomyza bryoniae)
- Chickpea leaf miner (Liriomyza cicerina)
- Serpentine leaf miner (Liriomyza huidobrensis)
- American serpentine leaf miner (Liriomyza trifolii).
The vegetable leaf miner, a native of the Americas, has spread to most parts of the world. It has established in the Torres Strait region and recently spread to Cape York in far north Queensland, where it is under official control to contain it.
Leaf miners threaten Australia’s vegetable, potato, melon, cotton, onion and grain crops as well as production nurseries.
Importing goods
To keep leaf miners out of Australia, never ignore Australia’s strict biosecurity rules.
Import shipments may need to be treated and certified, so before you import, check our Biosecurity Import Conditions system (BICON).
What to look for
- Trails or 'mines'—light green to white squiggles—on leaf surfaces.
- Sometimes a blackened stripe at the tunnel edge.
- Trails get wider as the grubs grow.
- Adult leaf miners are tiny flies—just 1-2 mm in length. Their colour varies with the particular species.
While similar damage could be caused by other leaf mining insects that are already in Australia, if you see squiggly leaf mines, particularly on a number of species of plant, don’t hesitate to report it.
Where to look
Importers
Importation of infested plants, plant material or soil is the most likely way that leaf miners could make it to Australia.
Growers and home gardeners
Look out for the tell-tale squiggly trails in crops and garden plants including:
- Tomato leaf miner – in many vegetables, mainly tomatoes
- Chickpea leaf miner – in legumes, mainly chickpeas.
- Serpentine leaf miner – 15 plant families, including beet, spinach, peas, beans, potatoes and cut flowers.
- Vegetable leaf miner – 40 hosts in 10 plant families, including capsicum, melon, cucumber, carrot, lettuce.
- American serpentine leaf miner – 28 plant families, including soybean, cotton, pea, potato, eggplant.
What to do
If you think you’ve found leaf miner trails or insects, and you live outside Cape York:
- take a photo
- contain the insects if possible (this may be as simple as closing the doors on a shipping container or preventing access to a vegetable plot).