Tasmanian farms at risk from new invasive pest, the serpentine leafminer

The invasive pest serpentine leafminer has been detected in Tasmania for the first time, with the species found at a commercial grower in the state's north-west. The insect damages the leaves of more than 200 host plant species, including potatoes, beans, peas, lettuce, celery and tomatoes, and can lead to reduced crop yields. What's next? Biosecurity Tasmania is undertaking surveillance and tracing, and urging the public to report specific sightings. Authorities are investigating Tasmania's first detection of the invasive serpentine leafminer. The high-risk pest affects horticultural and vegetable production systems, and has been present interstate since at least 2020. Biosecurity Tasmania said the insect was found at a commercial grower in the state's north-west. It said the species was known to affect more than 200 host plant species by damaging plant leaves and reducing their ability to photosynthesise — leading to reduced growth and crop yields. "Leafminers, including SLM (serpentine leafminer), create tunnels in plant leaves as they feed, leaving distinctive squiggly white lines on the leaf surface," Biosecurity Tasmania said. Biosecurity Tasmania said site-specific directions to control and minimise spread were in place, and it was undertaking "surveillance and tracing activities". The serpentine leafminer (Liriomyza huidobrensis) is a leaf-mining fly. Its larvae feed by tunnelling through plant leaves, causing "mines". Major crop hosts include potato, beans, peas, brassicas, lettuce, celery, tomato and pumpkins and other gourds. It also attacks some ornamental plants. Public asked to report Biosecurity Tasmania said other leafminer species were "very common" in Tasmania, but accurately diagnosing the serpentine leafminer was only possible through rearing larvae through to the adult stage, or through molecular testing. It has urged the public to aid monitoring by reporting specific cases of leafminer sightings. These include heavy leafminer infestations on commercially grown plants, particularly if the infested plants have not been infested previously, and leafminer damage on plants that are not commonly infested by the leafminer species already present in Tasmania. Those species include aster, artichoke, beans, calendula, carnations, celery, cucumber, coriander, gladiolus, marigolds, pumpkin, ranunculus, squash, sunflower, verbena, viola and zucchini.