Scientifically, no. There are a few structural differences and fruit flies tend to flock to kitchen waste while fungus gnats are attracted to organic materials such as compost and potted plants. However, English speakers in the US tend to use the terms interchangeably. Here in the South, we say gnat when we're technically referring to a fruit fly. Whatever you call these pesky insects, this homemade trap will rid your kitchen of the annoying pests.