The effects of different fungicides on the viability of entomopathogenic nematodes Steinernema feltiae (Filipjev), S. carpocapsae Weiser, and Heterorhabditis downesi Stock, Griffin & Burnell (Nematoda: Rhabditida) under laboratory condition

Ziga Laznik1*, Matej Vidrih1, Stanislav Trdan1

To increase our knowledge on the susceptibility of entomopathogenic nematodes (EPN) species to agrochemicals, the compatibility of the infective juveniles (IJ) of the EPN Steinernema feltiae, S. carpocapsae, and Heterorhabditis downesi with 15 chemical fungicides was investigated under laboratory conditions. The effect of direct IJ exposure to fungicides for 24 h was tested in a petri dish at 15, 20, and 25 °C. The results showed that the compatibility of S. feltiae with azoxystrobin was high, and similar findings were obtained for S. carpocapsae (strain C67) and all of the tested fungicides, except for tebuconazole + spiroxamine + triadimenol, maneb, dinocap, and copper (II) hydroxide + metalaxil-M. Nematode H. downesi (strain 3173) suffered the highest mortality rate when infective juveniles were mixed with tebuconazole + spiroxamine + triadimenol. The integration of the aforementioned agents into a pest management program is also discussed.

Keywords: Compatibility, fungicides, Heterorhabditis downesi, Steinernema carpocapsae, Steinernema feltiae, viability.
1University of Ljubljana, Biotechnical Faculty, Department of Agronomy, Jamnikarjeva 101, SI-1111 Ljubljana, Slovenia. *Corresponding author (ziga.laznik@bf.uni-lj.si).