These flatworms are invasive species in the US and are believed to have come from Asia. They are predators on earthworms. Members of this species have been reported across the northern states from the East to the West coast of the US. The flatworms are tan/yellow with a single dark stripe along the length of the back and a dark head. They reach a maximum of about 4 inches. A researcher at the State University of New York at Cortland (Pete Ducey in the Biology Dept.) is studying terrestrial planarians, there spread and ecological effects. He is interested in receiving reports of sightings of these cool animals.
On Jul 21, 2007, Bevs_garden from Tustin, CA (Zone 9b) wrote:
I've lived here in southern California for decades and never seen any planarians in until recently. I'm not sure which species are in my backyard.... this invasive one or some other one. Next time I see one I'd like to be able to positively identify it. Could someone please post what characteristics would help me distinguish one from the other?
On Oct 14, 2011, DancingTree from Ceres, CA (Zone 9b) wrote:
After 30 years of living and gardening in the same place, this year I've begun to find both kinds of land planarians in my garden - Bipalium kewense (long, brown with 2 stripes) and Bipalium adventitium (shorter, yellowish, one stripe). They hide under moist planters, pots, bricks. So I began using their hideouts as "traps", places I check to find them so I can then kill them. To kill them, I drop the planarians into a lidded plastic container (yogurt cup) that has 1/4" of diatomaceous earth in the bottom. I secure the lid. It works! I go out and hunt them after I irrigate, after rains, and in the morning. I check my "traps" and am regularly finding planarians. Physical / mechanical control is effective. By killing the adults, they cannot reproduce or increase populations. This way I'm protecting my earthworms.
On Mar 9, 2012, phantera from Norristown, PA wrote:
If anyone finds one of these worms in SouthEast PA and wants to get rid of it please let me know - we teach about flatworms in our biology class and would love to have some of these to show the kids. (And I won't release the worm - they'll stay in captivity forever, don't worry.)