Quantitative comparison for some immune responses among Eurygaster integriceps, Ephestia kuehniella and Zophobas morio against the entomopathogenic fungus Beuveria bassiana

Some defense reactions including cuticular lipids, phagocytic activity, nodulation and hemolymph phenoloxidasec activity were compared in Eurygaster integriceps, Ephestia kuehniella and Zophobas morio exposed to five different B. bassiana isolates. The cuticular lipids were stimulating on conidia germination possibly with no fungicidal or fungistatic ability in epicuticular fatty acids. There was correlation between all studied immune system reactions and the virulence of isolates to E. kuehniella and E. integriceps. DE as a less virulent fungal isolate stimulated immune reactions in high levels in most experiments, despite of TV as the most virulent isolate. E. integriceps was the most sensitive host with lowered immune reactions. Z. morio showed resistant with the highest nodulation. E. kuehniella had moderate sensitivity with maximal phagocytic and the phenoloxidase activity. The phagocytic activity was the highest at 30 min after fungus injection. The nodulation and the phenoloxidase activity were demonstrated at 6, 12 and 24 h after injection. The most nodulation rate was observed at 24 h. The phenoloxidase activity for the most isolates reached a maximum value for Z. morio and E. integriceps after 12 h and in E. kuehniella after 24 h. Our research provides an interesting perspective in host susceptibility to fungal infections.