Leaf scorch, sometimes called marginal leaf burn, describes the death of tissue along the edge of the leaf.
This symptom develops when sufficient water does not reach the leaf margin cells. This can occur if 1) there is insufficient moisture in the soil 2) water is lost too quickly from the leaves to be replaced adequately, 3)roots have been killed by plant pathogens, excavation, or compaction or 4) fungi or bacteria invade and plug the water conducting vessels (xylem) in the plant.