Polyphasic taxonomy of entomopathogenic fungi infecting scale insects in Clavicipitaceae (Hypocreales) from China

Entomopathogenic fungi in Clavicipitaceae (Hypocreales) serve as critical regulators of scale insect populations in agricultural and forest ecosystems, playing irreplaceable roles in natural pest control and exhibiting considerable potential for biological control applications. Despite their ecological importance, the species diversity and phylogenetic relationships of these fungi remain significantly understudied in Southwestern China, especially in Sichuan Province.

In this study, we surveyed scale-insect pathogenic fungi across various forest ecosystems in Sichuan. Based on morphological observations and multi-locus phylogenetic analyses (LSU, tef 1 - α, rpb 1), 24 specimens were classified into 9 species in 4 genera: Conoideocrella, Hypocrella, Helicocollum, Regiocrella, including 5 new species and 4 new provincial distribution records. Furthermore, this study proposes the synonym of C. tiankengensis under C. luteorostrata.

Detailed comparisons and discussions of morphologically similar species and phylogenetically related taxa are provided. Comprehensive descriptions of phenotypic features, including fungal colony morphology, micromorphology, physiology, and ecology, are supplemented with illustrations and notes for all taxa. This study significantly enriches the species diversity and morphological knowledge of entomopathogenic fungi in Clavicipitaceae associated with scale insects in Southwest China, and provides new insights into their phylogeny, host associations, morphological evolution, and biological control of pest insects.