Abstract The entomopathogenic nematode Heterorhabditis bacteriophora is an active ingredient of several biological plant protection products, generally applied using motorised sprayers. The effect of hydraulic agitation of motorised sprayers on the viability of the entomopathogenic nematode was investigated in three experiments, which evaluated initial liquid temperature, hydraulic agitation and rise in liquid temperature as a result of agitation at initial water temperatures of 20 and 30 °C and four different spraying duration times (95, 48, 32, and 24 min), obtained by using various nozzle sizes (TeeJet flat fan nozzles 11008 VK, 11006 VK, 11004 VK, and 11002 VK). Viability was significantly affected ( p