Now that I've suddenly got this project about organisms about which I know ZERO, I thought it might be helpful to collect some literature about identifying mould.
Please add whatever you find in the comments.

Here are the first I found:
Guide to identify common cherry rot pathogens https://www.utas.edu.au/__data/assets/pdf_file/0011/1662464/Cherry-rot-ID-guide_final_2016.pdf

Moho verde en cítricos (Green mold in citrus fruits, Penicillium digitatum; Spanish)
https://herbariofitopatologia.agro.uba.ar/?page_id=319

A Comprehensive Review of the Pear Fungal Diseases
https://www.tandfonline.com/doi/epdf/10.1080/15538362.2016.1178621?needAccess=true

Schimmelarten und Schimmelpilzgattungen an overview in German
https://www.schimmelpilz-fachzentrum.de/ursachen/schimmelarten#

If you really want to get into identification, cultivation, microscopy etc. check this out:
Moulds, their isolation, cultivation and identification
http://website.nbm-mnb.ca/mycologywebpages/moulds/Moulds.html

And there is a book in German and its English translation:
Liliane E. Petrini, Orlando Petrini: Schimmelpilze und deren Bestimmung ISBN 978-3-443-50039-9, € 44,80 Sample pages in German: https://content5.schweizerbart.de/web/viewer.html?file=/download/WKpaeN07BZmBmn9WUAWuBCBePSoyNh
Liliane E. Petrini, Orlando Petrini: Identifying Moulds – A Practical Guide ISBN 978-3-443-50038-2, € 44.80 menos ↑