From 2021 to 2023, this project increased awareness and significance of three leafminer pests (serpentine leafminer, American serpentine leafminer and vegetable leafminer), their host range, how they are suited to various regions, what to look out for, and the significance of beneficial insects in managing them and how to look after these beneficial insects by selectively using insecticides.

In October 2020, serpentine leafminer was detected in western Sydney, New South Wales and soon after in the Fassifern Valley west of Brisbane, Queensland. The American serpentine leafminer followed suit, arriving in far north QLD, NT and Kununurra WA in 2021, and vegetable leafminer has been present in Australia since 2015. These introduced leafminers can significantly impact a wide range of commercial crops (vegetables, broadacre, ornamentals and non-commercial hosts) and are categorised as high priority pests and considered a serious threat to these industries.

This multi-industry collaboration incorporated organisations with recent, relevant R&D into leafminers as well as field scientists located in affected regions. The multidisciplinary team developed and delivered specific Liriomyza information with emphasis on the species found within the regions and facilitated a targeted communication program, which is critical if susceptible horticultural industries are to better understand and manage these pests.

The grower guide Monitoring for serpentine leafminer in Australia provides information for conducting effective and efficient monitoring of these pests in Australia.  Four grower guides (vegetable, potatoes, melons and onions) address the differences in management considerations that will occur between different cropping systems. An Industry Management Plan (IMP) includes many aspects of managing these pests by the industry, engaging with relevant stakeholders to ensure effective business and trade continuity.

Key R&D outputs from the project have been a refinement for the eDNA assays for L. sativae, L. trifolii and L. huidobrensis (Sooda et al. 2017) and L. brassicae (Pirtle et al. 2021). This test can now determine the presence of 2 additional leafminers, L. bryoniae, L chinensis.  Real-time qPCR assays were compared with a small portable qPCR machine for use in the field. This was done for L. brassicae and L. huidobrensis in the field with results for flies and larvae comparable to those achieved in the laboratory.  This project developed two LAMP (Loop-Mediated Isothermal Amplification) tests that are highly sensitive and specific for serpentine leafminer identification using Genie III machine. For direct visualisation of the test result in field, this project evaluated a colorimetric method for identification.

Extension efforts have been broad ranging with the project team delivering 16 workshops, three webinars, two field days, four grower and agronomist meetings, two conferences, two melon roadshows and visiting 46 farms.