Commonly found on roses during hot summers. Caused mostly by watering where salt in the water is deposited on the leaves along the edges and the sun evaporates the water leaving the salt which then burns these areas.
Solution is to avoid getting too much water on the leaves with watering. Using drip irrigation is both more efficient and also eliminates this problem.
Properties close to the sea can also see this problem occur. In these cases it is best to wash plants with a hose after it is suspected salty winds may have deposited salt on the plants.
Have seen this occur with foliage sprays where the same action takes place.