The effectiveness of hot water pressurized spray in field conditions to slow the spread of invasive alien species

An array of vectors have been identified that pose a risk spreading invasive alien species (IAS), from personal protective equipment to large such as vehicles and boats. Biosecurity practices remove and/or kill IAS reduce the accidental spread. The effectiveness biosecurity protocols suitable for is little tested requires development. One widely-used method high-pressure hot water spray machines. This study tests induce mortality in two aquatic plants: floating pennywort (Hydrocotyle ranunculoides) Australian swamp-stonecrop (Crassula helmsii); invertebrates: killer shrimp (Dikerogammarus villosus) zebra mussel (Dreissena polymorpha) field conditions. were exposed range durations (5–15 seconds) distances (10–30 cm). Further treatments up 90 seconds applied C. helmsii. Complete survival D. polymorpha, villosus helmsii was seen all control following exposure cold spray. Hot caused complete polymorpha at 10 cm 15 seconds, demonstrating treatment inducing mortality. However, less effective when longer shorter durations. In contrast, ineffective causing helmsii, even exposure. Fragmentation H. ranunculoides spray, therefore pressure associated with use against animals here, however ensure mortality, importance both duration distance application highlighted. did cause but not need containment safe disposal paramount prevent spread potentially viable propagules.