Five new species of Moelleriella infecting scale insects (Coccidae) in Thailand

The genus Moelleriella mostly occur on scale insects and whiteflies. It is characterized by producing brightly colored stromata, obpyriform to subglobose perithecia, cylindrical asci, disarticulating ascospores inside the ascus, and fusiform conidia, predominantly found in tropical and occasionally subtropical regions. Scale insects and whiteflies’ pathogens were found during our surveys and collections of entomopathogenic fungi. Investigations of morphological characters and multi-locus phylogenetic analyses based on partial sequences of LSU, TEF, and RPB1 were made. Five new species of Moelleriella are described here, including M. chiangmaiensis, M. flava, M. kanchanaburiensis, M. nanensis, and M. nivea. They were found on scale insects, mostly forming flat to thin, umbonate, whitish stromata. Their anamorphic and teleomorphic states were mostly often on the same stroma, possessing obpyriform perithecia, cylindrical asci with disarticulating ascospores. Their conidiomata are widely open with several locules per stroma, containing cylindrical phialides and fusiform conidia. However, M. flava has yellow stromata with one conidioma per stroma, and M. kanchanaburiensis was found only in its anamorphic state. Furthermore, the perithecia of M. nanensis were completely embedded in stromata as opposed to other species with semi-immersed perithecia. We also found a teleomorph link to M. sinensis, a species described based on anamorphic stage previously reported from southeastern China.