We cannot answer that question for you. You are definitely not required, however, if your state requires a termite letter at the time of closing, only professional companies can issue these letters and if you do not have an active contract with a company you will usually be forced to pay a large sum to have your house treated to get a clearance letter. You should call your state Department of Agriculture which is usually the department that manages pest control companies and ask if your state is one that requires a termite closing letter when selling a house.
It would be a great benefit to add a barrier spray outside using Termidor SC.
Termidor SC is a very safe product and widely used by professional companies inside homes every day across the country. Termidor SC is odorless and does not have any fumes. You only need to wear a face mask if you will be doing the application in a poorly ventilated or enclosed area. All other applications will require you to wear long sleeves, long pants, shoes and socks and gloves. Be sure to wash your hands after the application before you eat, drink, chew gum or use the restroom.
Just about any 1 gallon pump sprayer will do. We prefer the Chapin Premier 1 Gallon Pump Sprayer 21210XP because of the brass construction in the shutoff valve, wand, and nozzle. The nozzle is adjustable and using the pin stream spray would allow you to spray through a hole in the wall. All of the parts are replaceable when they wear out and when cared for properly will last for many years. You may want to look over our How To Do A Termite Treatment article to learn how you can protect the rest of your home against termites in the future.
Termites do not normally attack live, healthy trees so you most likely will not find any products that will work as a ground barrier around the trees. Most people are primarily concerned with protecting the big investment, their home, and Termidor SC would be the product to use for that. It is only labeled to be used adjacent to the structure though. Please take a moment to read over our article on "How to do a Termite Treatment" for complete details.