Q.Strange bug destroying bushes
We found just now that many bushes in the back of our garden look dry and dead, and found they are infested with some bugs. We moved to this house last year and never had a garden before so we are new to all this. Last year I fumigated, myself, the bushes in front but not at the back.
I believe we need to fumigate again. We will buy the equipment and the chemicals needed, but want to know if the plants still will have a chance or we will have to take them out and replant something else (are quite a lot). Also, would like to know what type of bug it is and if we should look for a specific product. Thank you for any help you can give us.

Without knowing the plant and the pest you are dealing with, it is difficult for me to tell you how to correct the issues.
We do recommend Neem Oil for most sucking insect infestations. It also works as a fungicide.
Neem Oil is organic and is safe for people, pets and bees.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm