Conoideocrella luteorostrata (Hypocreales: Claviciptaceae), a potential biocontrol fungus for elongate hemlock scale in United States Christmas tree production areas

The entomopathogenic fungus Conoideocrella luteorostrata , which is known to infect armored scale insects and whiteflies in Thailand and Japan, has been recently found causing natural epizootics in elongate hemlock scales (EHS) in Christmas tree farms in the eastern United States. The fungus was isolated from mycosed EHS, but not from the surrounding Fraser fir needles, which suggests that the life cycle is restricted to the insect host. This fungus is a promising candidate for biocontrol of EHS since it infects scales naturally and when applied under lab conditions, thus confirming pathogenicity of Conoideocrella luteorostrata against EHS, an essential first step in developing it as a biocontrol. Comparisons of multiple locus sequence data generated from isolates spanning multiple sites in North Carolina support a single clonal strain impacting United States EHS populations. Our results suggest that this biocontrol fungus merits further investigation and development as an agent targeting EHS in Christmas tree farms and surrounding hemlock forests. ### Competing Interest Statement The authors have declared no competing interest.