2.2. Null-hyperparasitism

It may happen that a hyperparasite is attacked by another parasite (Gállego Berenguer, 2007). Borkar (2020) refers to these secondary hyperparasites as null-hyperparasites, as they “nullify” the biocontrol activity of the primary hyperparasite. In a recent in-vivo experiment, this author showed that strains of Aspergillus niger and Bacillus thermophilus have the ability to parasitize the fungus Trichoderma hamatum, a common hyperparasite of the groundnut pathogen, Sclerotium rolfsii.