BIOSECURITY ALERT: Serpentine leafminer detected in western Sydney

Friday, 5 November 2020

Serpentine leafminer has been detected infesting field-grown vegetables in western Sydney in October 2020.

These flies in the genus Liriomyza pose significant risk to Australia’s horticulture sector, and growers are urged to be vigilant with monitoring and implement rigorous plant protection protocols to reduce the risk of further infestation.

Current data suggests this leafminer has 365 host plant species from 49 plant families, including vegetables (cucurbits, tomatoes, chillies, brassicas, lettuce, etc), ornamentals (gerberas, roses, dahlia, chrysanthemums, petunias, violas, etc) and many common weed species.

Plants damaged by this pest commonly suffer reduced yield and growth, and in some cases are completely destroyed.

Serpentine leafminer is widely distributed across the Americas, Asia, Africa, Middle East and Europe, and has shown that it’s able to quickly develop insecticide resistance, making it difficult to control.

About the Serpentine leafminer

Larvae feed internally on plant tissue, creating the classic mining trails that are associated with infestation, and then pupates in the substrate beneath the plants and hatch out as flies which then lay eggs on surrounding host plants.

Female flies puncture the leaves of host plants causing wounds which serve as sites for feeding. Feeding punctures of Serpentine leafminer are rounded, usually about 0.2 mm in diameter, and appear as white speckles on the upper leaf surface.

The Serpentine leafminer has a wide host range and can be easily confused with other species of leafminer. The appearance of their puncture and pattern of distribution on the leaf, also does not differ between Liriomyza species, which can make identification difficult.

The response

In response, New South Wales Department of Primary Industries (NSW DPI) and Greater Sydney Local Land Services (GS LLS) are mounting a response to delimit the current distribution of the pest with an eye to eradication or containment and control.

NSW DPI is urgently seeking industry assistance requesting any suspect detections/infestations be reported along with submitting samples for diagnosis.

For useful identification information and images please use the on-line pest identification platform www.pestid.com.au. Growers may also consider installing yellow sticky traps.

Report and submit samples

If you detect any signs of leaf mining in vegetables, please contact the Exotic Plant Pest Hotline on 1800 084 881 right away – early detection is vital for managing and eradicating pests and disease.

Photos of damage and adult leafminers can be sent to biosecurity@dpi.nsw.gov.au. Please contact NSW DPI on the above number or instructions on how to submit these for assessment. Your cooperation will assist in delimiting the spread of this unwanted new pest species.

For further information contact National Biosecurity Manager John McDonald via email at john.mcdonald@greenlifeindustry.com.au or call 07 3277 7900.

Note that the Pest ID tool is now available with free access to industry. An initiative of the Nursery Levy funded National Nursery Industry Biosecurity Program (NY15004) and ‘Building the resilience and on-farm biosecurity capacity of the Australian production nursery’ Project (NY15002).