Susceptibility of Spodoptera littoralis caterpillars to entomopathogenic nematode Steinernema feltiae after consumption of non-specific transgenic plants

Abstract

Spodoptera littoralis caterpillars were transferred from an artificial diet to potato leaves at the start of the third or fifth instar and exposed to the infective juveniles of the nematode Steinernema feltiae since the beginning of the sixth instar until the start of pupation. Leaves were taken from the control potatoes or from genetically modified potatoes expressing either Cry3Aa toxin of Bacillus thuringiensis (Bt) or Galanthus nivalis agglutinin (GNA) which are mainly non-specific to S. littoralis larvae. The nematodes killed all the caterpillars within seven days compared with the starved larvae in the same period of exposure. The average time to death and the number of nematodes successfully invaded the larvae were affected by the period of feeding on potato leaves. In the non-starved caterpillars, which received potato leaves throughout the whole period of exposure to the nematodes, the type of potato leaves had no effect on the number of nematodes inside cadavers (p = 0.352 and F = 1.070) and also on the effect on the length of survival after exposure to the nematodes (p = 0.7892 and F = 0.596). No hazardous effect on the development and survival of entomopathogenic nematode S. feltiae which successfully invaded larvae fed on modified potato (Bt or GNA) was reported.

Keywords:

• Steinernema feltiae
• Bacillus thuringiensis Cry3Aa toxin
• Galanthus nivalis agglutinin GNA
• Spodoptera littoralis

Acknowledgements

We are grateful to Dr. Zdeněk Mráček for his help and comments and to Mrs. Lenka Kropáčková for the supply of nematodes. This work was supported by the research program Z5007056 and a grant from the Agency of the Czech Republic (1M06030).