AbstractEradication of alien invasive species in the soil with steam as an alternative to chemical fumigation may allow contaminated soil to be reused. We have investigated steam disinfestation of soil to combat invasive plant species in three experiments including different temperatures and exposure durations using a prototype stationary soil-steaming device. The experiments included effects on seed germination of bigleaf lupine (Lupinus polyphyllusLindl.), ornamental jewelweed (Impatiens glanduliferaRoyle), and wild oat (Avena fatuaL.; one population from Poland and one from Norway), as well as effects on sprouting rhizome fragments of Canada goldenrod (Solidago canadensisL.) and Bohemian knotweed (ReynoutriaxbohemicaChrtek & Chrtková). In Experiment 1, we tested four different soil temperatures of 64, 75, 79, and 98 C with an exposure duration of 90 s. In Experiments 2 and 3, we tested exposure durations of 30, 90, and 180 s and 90, 180, and 540 s, respectively, at 98 C. Seed pretreatment of 14 d cooling forL. polyphyllusandI. glandulifera, no seed pretreatment and 12-h moistening forA. fatuapopulations, and 5- and 10-cm cutting size forR. xbohemicawere applied. Our results showed germination/sprouting was inhibited at 75 C forI.glandulifera(for 90 s) and 98 C for the other species; however, longer exposure duration was needed forL.polyphyllus. While 30 s at 98 C was enough to killA.fatuaseeds andS.canadensisandR. xbohemicarhizome fragments, 180-s exposure duration was needed to killL.polyphyllusseeds. The results showed promising control levels of invasive plant propagules in contaminated soil by steaming, supporting the steam treatment method as a potential way of disinfecting soil to prevent dispersal of invasive species.