Rugs and Dampness
Dampness will rot threads and destroy the fabric but it can be avoided with a bit of common sense.
Do NOT store rugs in a damp, warm or poorly ventilated room. Any of these is capable of causing mildew which has a musty odour, discolours fabrics, and weakens them so that they fall in pieces. Never leave an Oriental rug wet.
One of the most common causes of water damage comes from pot plants placed directly on a rug. If the plant is watered regularly and the pot leaks or is over-filled, the rug under the pot could easily have a permanently damp area. In this state, it could take as few as a couple of weeks for the rug to weaken enough for pieces to start separating.
The best advice is don't put plants directly onto your rug - use some means of separating them to allow plenty of ventilation and always check the rug is completely dry after plant watering.