Quiescence mechanism for survival in Steinernema rarum from Argentina

CAGNOLO, S.R.; DOUCET, M. E.; CAMPOS, V. E.

Campos dos Goytacazes, RJ

Congreso; 26° Congreso Brasileiro de Nematologia; 2006

CEFET e UENF

Nematodes may undergo a temporary quiescence stage in response to environmental stress. The storage period of infective juveniles (IJ) of entomopathogenic nematodes may be critical to affect their survival and infectivity, depending on the species or the isolates. The objective of this work was to evaluate the survival and infectivity of IJs of an Argentine isolate. To evaluate the survival, three behaviour categories were established: mobile (MJ), coiled immobile (CIJ), and elongated immobile juveniles (EIJ). Infectivity was evaluated through the host mortality percentage and the mean number of IJ that entered the host. Infections (12 replicates per category) were performed using 4 IJGalleria mellonella. At both temperaturas, IJs were mostly represented (95%) by MJ in the first week. Then, they gradually lost mobility and adopted the CIJ or EIJ shapes. EIJ were abundant from the fourth week onwards at 5°C and scarce at 23°C. Significant differences were found in EIJ infectivity in comparison to other categories (ANOVA, P