The answer to 'stone walkway disease' is that it can be caused by a variety of issues, including weed growth, moss buildup, cracking or crumbling, and uneven settling. Symptoms may include discoloration, cracks, or an uneven surface. Solutions can range from regular maintenance like weeding and power washing to more extensive repairs like resetting pavers or replacing damaged stones.
In many cases, homeowners can address minor issues like weeds and moss through DIY maintenance. However, for more significant problems like structural damage or uneven settling, it's best to consult a professional landscaper who can properly diagnose the issue and recommend the appropriate solution.