Nectria tuberculariformis, Nectriella muelleri, Nectriella sp., and Hyponectria sceptri: low-temperature tolerant, alpine–boreal fungal antagonists

Abstract

The ascomycetes Nectria tuberculariformis, Nectriella muelleri sp. nov., Nectriella sp., and Hyponectria sceptri comb. nov. were collected in alpine–boreal habitats. They were low temperature tolerant, growing at 0 °C and poorly or not at all at temperatures above 18 °C. Optimum temperature for spore germination and growth was 10–15 °C. Nectria tuberculariformis was found to be the teleomorph of Acremonium boreale; Nectriella muelleri and Nectriella sp. each had Acremonium anamorphs. No anamorph formed in cultures of Hyponectria sceptri. All four species produced a diffusible substance or substances that inhibited growth of the mesophilic plant parasites Chondrostereum purpureum, Fusarium solani, Glomerella cingulata, and Phoma medicaginis var. pinodella. Nectria tuberculariformis, Nectriella muelleri, Nectriella sp., and Hyponectria sceptri are described and illustrated.