If the neighbor that you are having a problem with is also a member of the association due to owning a home in the planned developement that you live in, read the recorded "conditions, covenants, and restrictions" recorded on your property and the association's rules presently in effect. The langiage in these documents will control what obligations the association have to enforce the common areas in the development.From your question and facts, the problem is not a physical condition of the common area that is causing a problem (raised sidewalk where someone trips and breaks an arm), but rather a difficult individual and presumed property owner.Your dispute is directly with the difficult neighbor. The association has no control over an individual's conduct directly towards another person as you describe.Your neighbor who placed the fertilizer on the common area that sickened your dog would be the one responsible for your veterinarian bills.