Management strategy for serpentine leafminer, Liriomyza huidobrensis

Abstract

The project commenced with a focus on Serpentine leafminer (SLM – Liriomyza huidobrensis), initially detected in western Sydney, New South Wales, October 2020 and soon after in the Fassifern Valley west of Brisbane, Queensland. The American serpentine leafminer (ASLM – Liriomyza trifolii) followed suit arriving in far north QLD, NT and Kununurra WA 2021. With the Vegetable leafminer (VLM – Liriomyza sativae) already in Australia since 2015 in far north QLD, Project MT16004 ‘RD&E program for control, eradication and preparedness for vegetable leafminer’. These introduced Liriomyza leafminers can significantly impact a wide range of commercial crops (vegetables, broadacre, ornamentals and non-commercial hosts); and categorised as high priority pests and considered a serious threat to these industries.

This multi-industry, QLD DAF led collaboration incorporates 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.

Key outputs 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 2 LAMP (Loop-Mediated Isothermal Amplification) tests that are highly sensitive and specific for serpentine leafminer identification using Genie III machine. For direct visualization of the test result in field, this project evaluated a colorimetric method for identification.

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.

Extension efforts have been broad ranging, delivering 16 workshops, 3 webinars, 2 field days, 4 grower and agronomist meetings, 2 conferences, 2 melon roadshows and visiting 46 farms. The key outcomes of this project have increased awareness and significance of these 3 leafminer pests, 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.

This project has developed a number of documents which will are available on the Ausveg website MT20005 – Management Strategy for serpentine leafminer (Liriomyza huidobrensis) | AUSVEG as well as 2 publications on the spread of these leafminers and using LAMP as a diagnostic tool to help identify at least SLM.