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 recentin-vivo experiment, this authorshowed that strains ofAspergillus niger and Bacillus thermophilus have the
ability to parasitize the fungus Trichoderma hamatum , a common
hyperparasite of the groundnut pathogen, Sclerotium rolfsii .