Call in the Pest Controller, this is not a job you can do without help!
Here's a post that might help - https://www.pesthow.com/how-to-get-rid-of-termites/
diesel fuel, use a pump sprayer and spray away.
i would definitely call a pro.......termites are usually infesting the actual structure of the house so, what you are seeing is only the tip of the iceberg!!