Preparing for the vegetable leafminer, an emerging biosecurity threat to Australian agriculture

cesar is at the forefront of a project addressing a new and significant biosecurity threat to Australia’s vegetable, nursery and melon industries: the vegetable leafminer (VLM, Liriomyza sativae).

VLM is an insect with a taste for a wide variety of fruit and vegetable crops, and is responsible for severe yield losses abroad. This is due largely to the destructive feeding of the larvae, which create serpentine mines in the leaf that hinder photosynthesis and reduce marketability of crops. Moreover, VLM can be tricky to control, thanks to their tendency to evolve resistance to insecticides (such as abamectin and several pyrethroids). ­­

In 2015, the first detection of VLM within the Australian mainland was made on Cape York Peninsula, and VLM is now considered at high risk of establishing within our major production zones. Australia’s increasing focus on international export, and current reliance on interstate trade, means keeping vegetable production areas free of trade-sensitive plant pests is critical. 

Horticulture Innovation Australia is funding a comprehensive project to increase industry preparedness for VLM incursions and provide scientifically robust guidelines for monitoring, eradicating, and managing VLM. cesar will be leading a strong and diverse team of partners, including the University of Melbourne, AUSVEG, Plant Health Australia and the North Australian Quarantine Authority. This team has diverse capabilities in pest surveillance, molecular diagnostics, computer modelling, pest control, incursion response, and industry engagement.

cesar researchers will be traveling to VLM incursion zones on the Northern Peninsula and Torres Strait Islands, where we will develop and test monitoring techniques, and collect specimens and distribution data for molecular and modelling approaches. As such, we will be working very closely with our partners at the Northern Australian Quarantine Strategy, and will also engage with the Torres Strait Regional Authority.

Here are some the project outcomes we can look forward to:

• We will develop easy to use surveillance toolkits that rely on simple invertebrate trapping protocols and a cutting edge molecular technology, eDNA, which can detect a species from a single drop of water (or from a sticky trap full of invertebrates), allowing for highly sensitive, rapid and cost-efficient processing of samples. These surveillance toolkits will allow for rapid responses to new VLM incursions within Australian production regions

• We will track the incursion pathway that VLM has followed to the Cape York Peninsula via next generation genome-based molecular methods. These methods will help us pinpoint the lineage of the invading VLM, and thereby help us anticipate and prepare for any characteristics specific to the invading population, such as insecticide resistance.

• We will identify regions within Australia that are at highest risk of a VLM incursion via sophisticated computer simulations. These simulations are based on biological traits of the VLM (such as their temperature tolerances, host plant preferences, dispersal abilities, and reproductive cycles) as well as environmental characteristics of the regions in question (such as temperature, humidity and wind patterns). This will create robust predictions of areas at highest risk of VLM establishment, allowing us to target our surveillance and incursion preparation efforts accordingly.

• We will develop information packages regarding chemical and biocontrol options for VLM eradication and management. These will include guidelines for effective chemical control of VLM, considering potential resistance issues, as well as pre-prepared emergency use permits, allowing for rapid responses in the event of new incursions. Moreover, we will investigate biocontrol options by identifying parasitoid species, within and outside of Australia, that can control VLM populations. Computer simulations will be used to identify parasitoids with the greatest chance of successfully establishing in regions threatened by VLM incursion. Together, these chemical and biocontrol options will form an improved integrated pest management approach that will facilitate the eradication and management of VLM in Australia.