A novel strain of Akanthomyces muscarius as a promising biological control agent against Toumeyella parvicornis

Abstract: Entomopathogenic fungi represent a valuable alternative to traditional agrochemicals for the sustainable protection of crops. Members of the genus Akanthomyces are already employed in biocontrol practices, particularly against aphids, thrips, whiteflies, and mites. However, the efficacy of this genus on soft scales remains poorly understood. The present study aimed to investigate the potential use of a novel strain of Akanthomyces muscarius on the soft scale insect Toumeyella parvicornis, a recently introduced invasive pest for European stone pines (Pinus pinea). The fungus was isolated from another soft scale insect, Parthenolecanium corni, on which it exhibited high infectivity. It has been subjected to molecular characterization and phylogenetic analysis. A series of bioassays were conducted to compare the efficacy of the novel strain with that of BCA contained in commercial formulations. Trials included overwintering females, post-overwintering females, and nymphs of T. parvicornis. The results demonstrated that this strain of A. muscarius successfully colonizes T. parvicornis, causing a rapid infection and death of the scale insects. The comparison with other available formulations suggests that our strain exhibits a higher pathogenicity on T. parvicornis. These findings encourage further research into the potential of this strain of A. muscarius as a biological control agent for the reduction of T. parvicornis infestations in the field.