Estonia warns earthworm-eating 'ocher flatworm' may hitchhike in potted plants

Disrupting those systems can have wider effects, harming gardens, farms, and local food production. A predatory flatworm known as the ocher flatworm is inching closer to Estonia, and officials warn that transporting potted plants, planting material, soil, and compost can easily bring in these species. While the worms aren't considered a direct danger to people, they feed on earthworms and other helpful soil organisms, which can harm biodiversity, gardens, and food systems. Here's what to know After the species was detected in Sweden in 2024 and in Finland, Estonia's Ministry of Climate said the country may face the arrival of the ocher flatworm, Obama nungara, as ERR News reported. According to officials, they likely can spread by hiding in potted plants, planting material, soil, and compost. ERR News reported that the land-dwelling flatworm originates in South America and preys on earthworms, snails, slugs, insect larvae, and other invertebrates living in soil. Those organisms are important for soil fertility, structure, moisture balance, and nutrient movement. Disrupting those systems can have wider effects, harming gardens, farms, and local food production. ERR News reported that Merike Linnamägi, an adviser in the Ministry of Climate's biodiversity protection department, said that the flatworm has been added to the EU's invasive alien species list. That means it is illegal to intentionally import, keep, breed, transport, sell, exchange, propagate, or release it into nature. More background Adult flatworms usually measure about 2 to 3.1 inches long, or 5 to 8 centimeters, and have a shiny, flattened body. Their back is brownish and may show dark stripes or a net-like pattern. The egg capsules are tiny, smooth, and about the size of a peppercorn, shifting over time from reddish to dark brown or black. Estonia's guidance says the flatworm is most active at dusk and during the night, so a headlamp can make it easier to spot both the animal and its slime trails. It's best when invasive species are detected early, since dealing with them is cheaper and far simpler than after they become established in the wild. What can be done? The ministry said businesses and individuals that import or sell potted plants from other European countries should inspect them closely, especially when soil or growing substrate is present. Bare-root plants are considered lower risk. Officials advise checking the outsides and undersides of pots as well as trays, boxes, and root balls. They also recommend wearing gloves during inspections because the animal's mucus can irritate the skin, and say that suspicious specimens should never be touched with bare hands. If someone thinks they have found one, ERR News reported that the guidance is to photograph it, place it in a sealed container or plastic bag, and freeze it. Officials also warned that suspicious material should not be thrown into compost or discarded in nature, because that could help the species spread further. ERR News reported that suspected sightings can be submitted by uploading a photo to Estonia's nature observations database or by using the PlutoF Go app. The ministry, Environmental Board, and other partners are also monitoring the flatworm in neighboring countries and updating guidance for sellers, landscapers, and gardeners when needed. "Early notification makes it possible to quickly assess whether it is this species and, if necessary, take measures before it spreads more widely. We ask the gardening sector and home gardeners not to wait with suspicious finds but to report them immediately," Linnamägi said. Where can I learn more? These stories help explain Estonia's warning, showing why earthworms are so important to healthy soil and how gardeners and land managers respond when pests disrupt ecosystems. They also highlight what is at stake for farms, compost systems, and backyard gardens if invasive species start to spread. • Researchers found earthworms boost global crop yields by improving soil conditions on farms worldwide. • Home gardeners are using worm composting tower systems to turn scraps into soil-friendly nutrients. • In Africa, CIFOR-ICRAF teams are testing new ways to manage invasive armyworms with fewer pesticides. Healthy soil depends on small organisms, and problems are much easier to contain when they are caught early. That's why officials encourage gardeners and plant sellers to keep a close eye out for this flatworm. Get TCD's free newsletters for easy tips, smart advice, and a chance to earn $5,000 toward home upgrades. To see more stories like this one, change your Google preferences here.