Survival of Steinernematid nematodes exposed to freezing

Entomopathogenic nematodes Steinernema riobravis, S. carpocapsae and S. glaseri survived prolonged exposure to freezing at −4°C. LT50 values were 2.1, 1.8 and 0.6 days respectively. Steinernema riobravis and S. carpocapsae were still pathogenic after 6 days of freezing and S. glaseri showed poor pathogenicity over 4 days of freezing at −4°C. Incubation in 20% glycerol for 48 h prior to freezing at −20°C enhanced survival and pathogenicity of S. carpocapsae. Survival increased to 30 days; nematodes were still pathogenic after 24 days of exposure.