If insects such as bees or non-diseased mosquitoes don't carry diseases but they bite or sting you, you may kill them on Jewish festivals, as well as trapping them or chasing them away with bug spray. Unlike on Shabbat, on a Jewish festival you may kill insects that are a nuisance, such as gnats or flies. These halachalot apply to all Jewish festivals unless they fall on Shabbat (or are Yom Kippur).