Have you got some micrographs of sporulation of the species? Mainly on decayed leaves ? It can be defined by microscopy first. The sequence , if needed, can be made if you know what approximately are you search for and if you need to tell apart morphologically similar species
Attempted microscopy but could not find any sexual fruiting structure which could help in identifying may be it is not making any sexual structure in our conditions
I guess, there is only way to wait for fruiting development...maybe in the end of vegetation season, when mature fruiting body may be observed. If mycelium stay sterile, the only way is DNA Sequence
It's possible to find a new species, as pathogens of such plants as Atriplex hortensis are traditionaly poor studied. I faced such problems for several times.