Elucidating the pathogenicity of Metarhizium to Euschistus heros (Hemiptera: Pentatomidae) eggs

Abstract

The ovicidal effect of entomopathogenic fungi and the mechanisms involved are still debated. The hypothesis that the metabolic activity of germinating conidia can cause insect embryos to become unviable without physical penetration has been proposed. Here, we demonstrated that Metarhizium anisopliae and Metarhizium pingshaense (in a different manner from Beauveria bassiana), reduced the percentage of nymphs hatching to less than 3%. They caused degradation of the egg wall due to the growth and penetration. The visualization of lipids being directed from the eggs towards the interior of the hyphae suggests that the lipid reserve was used as a source of nutrients for the development of these fungi.