His work principally concerned the taxonomy, chemistry, and toxicity of the gilled mushrooms (Agaricales), especially those of the genus Cortinarius, and the ecology of ectomycorrhizal relationships.
After completing his doctorate in 1950, Moser worked in England for six months, researching the symbiotic relationships between plants and fungi.
His father was a teacher at a technical college in the city, while his mother was the daughter of the botanist Emil Johann Lambert Heinricher.
Moser became an "authorized mushroom controller and instructor", and was in turn directed to attend mycological seminars around Germany and Austria.
[3] In 1945, when Moser was 21 years old and still carrying out active military service,[2] he was captured in Czechoslovakia by Soviet soldiers and made a prisoner of war.
[6] In 1950, under the supervision of the botanist Arthur Pisek, Moser completed his doctoral thesis, Zur Wasserökologie der höheren Pilze, mit besonderer Berücksichtigung von Waldbrandflächen [Water Ecology in Higher Fungi with Special Emphasis on Forest-Fire Areas].
[7] Having become friends with prominent German mycologists during the War,[8] he was keen to re-establish academic relationships throughout Europe in the years following the conflict's resolution.
[7] Due to the quality of his doctoral work, Moser received a grant from the British Council and in 1951 moved to England, where he stayed for six months.
[11] It served as an update to the mycologist Adalbert Ricken's 1918 Vademecum für Pilzfreunde [Handbook for Mushroom Hunters], though reflecting Moser's taxonomic views, which were highly influenced by Singer.
[10] The work, which became known simply as "Moser", was updated and republished numerous times over the following decades, and translated into both Italian and English,[11] with the latter being by the naturalist Roger Phillips.
[14] The work continued to be used as a standard reference for several decades; in 1981, it was still, in the words of the mycologist Richard P. Korf, "the most-used and most authoritative handbook on larger European fleshy fungi".
[17] Unlike the previous three books in the series, which were all written by German authors, the work addressed mushrooms that were of less interest to amateur mycologists; for instance, Phlegmacium was not considered to contain any significant edible species.
[14] The illustrations, which came in the form of coloured plates,[18] were mostly Moser's own work; Singer described these in a review of the book as "both in original execution and reproduction among the best that have been published".
[19] Discussing the book as a whole, Singer said that the volume, "outstanding for its good print, attractive appearance, and interesting contents, should be present in every mycological library".
[19] In 1963, Moser published a second work in Kleine Kryptogamenflora von Mitteleuropa,[11] Ascomyceten (Schlauchpilze) [Ascomycota (Sac Fungi)].
Korf, reviewing the work for Mycologia, said that "the book belongs on the shelf of every mycological library in Europe", praising the "[e]xcellent, workable keys to the orders, families, genera, and European species".
Moser was the only candidate for the position, and was unanimously named by a number of leading European botanists and mycologists for the post in 1967.
It was a study of South American Cortinarius, Stephanopus – a genus described in this work for the first time – and Dermocybe taxa, containing descriptions of 276 new species.
The piece, compiled by the microbiologist Franz Schinner, the mycologist Cuno Furrer-Ziogas, and Horak, contained a detailed biography of Moser and a full bibliography of the 116 research publications he had authored or co-authored between 1949 and 1983.
[26] Writing with Walter Jülich, Moser published the first volume of the book series Farbatlas der Basidiomyzeten [Colour Atlas of the Basidiomycytes] in 1985, presenting specimens of various Basidiomycota taxa.
[28] In 1991, Moser retired from his teaching position to avoid the administrative burden and to focus on his research into Cortinarius and related genera.
[29] In 1992, he researched the presence of Agaricales in the Crimean Mountains, identifying approximately 70 species that were not documented (or highly rare) in the region, including some new to science.
His former students, assistants and collaborators at the Microbiological Institute at the University of Innsbruck, his professional colleagues in the mycological community worldwide and his many friends will deeply regret the loss of a distinguished researcher, teacher, leader and mentor.
"[42] In a short obituary as part of their report on the Eighth International Symposium on Arctic-Alpine Mycology, the mycologists Cathy Cripps and Joe Ammirati called Moser a "gentlemanly scholar" who "led us in his quiet way across the tundra and down many dichotomous paths".
[45] In the early decades of his career, Moser sought to clarify the taxonomic identity of European fungi by collecting specimens to be described as neotypes in the localities studied by the mycologist Elias Magnus Fries, but this was no longer necessary after changes to nomenclatural rules that took effect in 1981.
He published book-length works addressing Cortinarius taxa found in Europe and, co-writing with Horak, South America.
[46] Moser, working with Ammirati, contributed to research on the genus in North America,[12] and also examined Asian and Australasian taxa.
[8] He was known as an intellectual and a wide reader, with interests in fine art, classical music, literature, exploration, geography, and botany.
[50] He was a capable cook, often creating mushroom-based dishes for guests, though he was on one occasion poisoned during "gastronomic experiments" involving Phaeolepiota aurea (the golden bootleg) and Agaricus mushrooms.