I am interested to see what ppl have to say about this. Last year after we first moved in we had some in the flower beds by the house so I removed all the wood mulch and used pine needle mulch last year. Which it turned out I really didn't like its upkeep so this year we used compost. It looks nice. I haven't seen any termites this year or last summer, so hopefully it is helping. Time will tell.

Just out of curiosity, what are the termites feeding on under the flower bed?

It's something of a myth that termites infest wood mulch. It's also a myth that cedar mulch repels termites and other insects. You should keep wood mulch products, however, away from the foundation of your home.

It would be difficult to recommend one mulch over another in regards to termites. Even if they don't feed on the product, they can live in the cool, moist soil that mulch creates. They will forage for their food.

We use pine BARK chips around the foundation. Not much food in that product for termites. But we also keep it several inches away from the home.

Tree stumps were buried under the soil and gravel by the pervious owner that we didn't know. As the neighbor's trees grow taller and bigger block most of the sun, only a few weeds and hosta can grow at the backyard, and soil erosion exposes the stumps that was how I've found out. And on the other side of the fence, my neighbor has a huge firewood pile there for more than two years. My lot is very small.

I'm just wondering was the previous owners knew about that, was that the reason they mulched the area next to the driveway with gravel and under the deck, and when they built the deck, they used compiste wood and mental posts? It's not common using these materials in my town.

From my own experience, I made a compost pile next to the termite colony (I didn't know about the termites) last spring. This spring I removed it and used the area for new plantig area. When I dug holes there were no termites or signs of their activities. But,I grew up in a big city (my home was on 21st floor). I have very little knowledge about insects.

The mulch at the foundation bed is completely composted, it was done by the previous owners. I usually don't rake up the leaves at fall until next spring to give the plants extra protection.
When I read the contact of the termite service, they terms state that any cellose debris will affect the treatment effectiveness.

In our area, one in 3 homes has some termite demages. Now I'm in a tough position. Even compost mulch still provides a perfect condition for them to live. Even the treated woods still can be a potential food for the termite down the road. Sholud replace the fence with the plastic one? Should I stop gardening for that reason? Then my life would become all about termite. I've got to live a little.

Bark is made up of lignin not the cellulose of wood which is the food of termites. Using bark where the exterminators apply their stuff will not negate your warranty. Keeping any mulch away from the building, as Rhizo mentioned, will keep the termites from entering your house. Google 'termites' or 'termite control' to get more detailed info.