Oligolectic on Asteraceae with a preference for Cichorioideae; species of the Asteroideae are exploited as well; pollen records of Carduoideae are lacking so far (Amiet et al., 2004; A. Müller, unpublished, based on 33 pollen samples from 25 different localities and on field observations). Müller (2018) in a further study (based on 50 pollen loads from 42 different localitiesacross the geographical range of the species and on field observations) states that among the Asteraceae, Osmia scutellaris only exploits species of Asteroideae and Cichorioideae with a preference for the latter subfamily: 35 of the pollen loads studied were of pure Cichorioideae pollen and eight were pure Asteroideae pollen. Seven were mixed loads consisting of the pollen of both subfamilies.
Banaszak & Romasenko (1989) list the following plant genera as forage sources: Asteraceae, Fabaceae and Rosaceae.
Pesenko in Banaszak (1995) states that this is an oligolectic species, specialising in Asteraceae. Mavromoustakis (1948; 1951; 1952) lists Anthemis sp, and unspecified Asteraceae, and Marrubium vulgare apolum (Lamiaceae) as a forage source in Cyprus
Ivanov et al. (2005) states that the species is polylectic and prefers Lamiaceae, Fabaceae and Asteraceae.
Müller (2018) also lists the following visitation data: Anthemis chia, Chrysanthemum coronarium, Crepis aculeata, Inula sp., Pallenis spinosa, Picris sp., Sonchus asper, Thrincia sp., Urospermum picroides (ASteraceae).