In 1984–5 and 1985–6 aerosporological data were collected in an experimental hazel-nut orchard in Cravanzana (High Langa) whereCorylus maxima andCorylus avellana cv. Tonda Gentile delle Langhe (TGL) were present with a prevalence of the latter. Inter variety crosses withC. avellana and interspecific hybridsC. avellana xC. maxima were also present. CultivatedCorylus flowering diagrams are known, while more evidence is needed on the spread and concentration of airborne pollens, especially during female anthesis which spans over a month on average. Pollen release periods were identified including onset of accessory periods. Aerosporological data helped identify TGL association in relation to spread of plants and quality of nut. Cultivars and hybrids, which have already been studied in terms of genetic compatibility, have been considered in terms of airborne pollen periods. Thanks to adequate pollinators we can rationalize orchards, increase productivity while maintaining nut quality. This work has been supported by “Ministero della Pubblica Istruzione” found 60%.