I need some advice on suspected tree insects. Our house is in Eagan and the property has old growth Burr Oak and Red Oak trees. I had 2 tree service companies give me bids on some tree work last year. Both mentioned the 2 Burr Oaks probably are infested with "Two Line Chestnut Borer" due to last years severe drought. One suggested lots of watering with a soaker hose and the other recommended injecting the tree with an insecticide. The grounds keeper that is at my work said "once you start injecting the tree, you have to treat it every 2 years for the life of the tree. I went online to research the insect on how to help the tree and I got some good advice. However, I could not find anything on if the insecticide is something that has to be done every 2 years forever. Do you have any advice on this and any other advice on this dreaded insect. Thank you for your time.