Question:
Can I open the sealed packages of Aravos and Haddasim on Yom Tov itself as they remaining fresher in the sealed packages?
Answer:
Opening the bag in a way that ruins it, is permitted on Yom Tov, however the hadasim should be tied to the lulav and should not be tied on Yom Tov. As a side point, if you put a wet towel around the aravos before yom tov, it will help keep them fresh.
Best wishes