Biological characterisation of Heterorhabditis atacamensis and Steinernema unicornum (Nematoda: Rhabditida), entomopathogenic nematodes from Chile

摘要

This is a bionomic study of the entomopathogenic nematodes (EPN) Heterorhabditis atacamensis and Steinernema unicornum, from the Atacama Desert and Tierra del Fuego in Chile, respectively. At 20°C, H. atacamensis infective juveniles took 22 days to emerge from cadavers, S. unicornum took 24 days. The thermal infectivity range for H. atacamensis was wider than S. unicornum (10-35°C vs 10-30°C). Exposure to 37°C for 60 min killed 100% H. atacamensis and 57% 5. unicornum. Heterorhabditis atacamensiscaused 53% insect mortality at the lower end of the soil moisture range, S. unicornum caused 100%; both caused > 85% mortality at the upper end (near saturation point). Heterorhabditis atacamensis killed three of six insect species; however, mortality was relatively low for each (< 35%). Steinernema unicornum killed five of six species, with mortality consistently > 50%; mortality of the fruit tree weevil Naupactus xanthographus was highest (90%).