Morphological and phylogenetic analyses reveal novel entomopathogenic fungi infecting scale insects and aphids in China

Entomopathogenic fungi exhibit a cosmopolitan distribution across diverse ecosystems, with their ubiquitous presence intrinsically linked to insect habitats-essentially occurring wherever insect populations exist. These fungi represent a vital biological resource, particularly in agriculture and forestry. They serve as a crucial repository of fungal strains for biological pest control. This investigation identified seven species from southwest China based on multi-gene (ITS, LSU, SSU, <i>act</i>, <i>rpb</i>1, <i>rpb</i>2, and <i>tef</i>1-α) phylogenetic analyses and morphological characteristics, including one new species and one newly recorded species in <i>Cladosporium (Cladosporiaceae)</i>; four new species in <i>Moelleriella (Clavicipitaceae)</i>; and one new species in <i>Podonectria (Podonectriaceae)</i>. All seven fungi are in their asexual morphs and were discovered on aphids or scale insects, which are common and significant pests. These include <i>Cladosporium kuwanaspidis</i>, <i>Cladosporium guizhouense</i>, <i>Moelleriella eucalypti</i>, <i>Moelleriella boehmeriae</i>, <i>Moelleriella cinnamomum</i>, <i>Moelleriella citrus</i>, and <i>Podonectria multiarmata</i>. Descriptions and illustrations for all seven taxa are provided. Six of these species were collected from scale insects, specifically those found in bamboo forests, broad-leaved forests, or understory vegetation, and one was collected from aphids, primarily distributed on the underside of night-blooming jasmine leaves. This work reveals the rich diversity of entomopathogenic fungi in southwestern China, not only on larger insects such as Lepidoptera and Hymenoptera but also on smaller Hemiptera, many of which are significant agricultural and forestry pests. This study contributes fungal resources that may support the development of innovative pest control methods in the future.