A word translated “autumn, harvest” in The Lord of the Rings appendices (LotR/1111), clearly based on yávë “fruit”. This word referred to the third out of six “official” Elvish seasons in the Calendar of Imladris (LotR/1107), but could also be used more causally for the autumn time of the year (LotR/1111). Given its second gloss “harvest”, I think it can also refer to the time or act of harvesting of crops. However, for the harvest itself (the produce) I would instead use [ᴺQ.] salcessë.
Conceptual Development: The Qenya Lexicon of the 1910s had ᴱQ. Yāvan “(Autumn), Harvest” based on ᴱQ. yāva “fruit, produce” (QL/105). The English-Qenya Dictionary of the 1920s also had ᴱQ. yávan “autumn, harvest”, but in that document the word was deleted (QL/69).
yávië noun "autumn" (SA:yávë); "autumn, harvest", in the calendar of Imladris a precisely defined period of 54 days, but also used without any exact definition (Appendix D). Noun yáviérë *"Autumn-day", a day outside the months in the Steward's Reckoning, inserted between Yavannië and Narquelië (September and October) (Appendix D)