Salty well water and/or city water sprayed on foliage can cause burn. It can cause even more serious long term problems in the soil. Most all of the organic soil amendments help neutralize short term and long term sat problems. Injecting liquids such as compost tea, Garrett Juice and/or liquid humate into the irrigation lines is very beneficial and will eliminate even the cosmetic burn on the foliage. And the most important step - stop using synthetic fertilizers. They are basically salts.