Is it true that there is a prophetic hadith stating that a disease descends from the sky on a certain day of the year, entering every uncovered vessel, which necessitates discarding uncovered food for fear of wastefulness, and if it is not true, is that considered wastefulness?

The Prophet, peace and blessings be upon him, commanded covering vessels at night. It is mentioned in the Hadith (definition) that this is because there is a night in the year when an epidemic descends, and it does not pass by an uncovered vessel or waterskin without the epidemic descending into it. This Hadith is authentic. As for discarding food in the trash, it should be avoided due to the prohibition of wasting money. It can be fed to animals or left for birds.