A differential incidence of subterminal die-back was observed in the several tratments of a NPK 2x2x2 factorial experiment whose plants are 11 years old. In each tratment the number of affected individuals was counted. Leaf samples were collected and the macronutrient content therein was determined. The statistical analysis of the results has shown that: a) The use of nitrogen has significantly reduced the number of abnormal plants. b) A negative highly significant correlation coefficient was found between leaf nitrogen and number of affected individuals. c) It is likely, therefore, that nitrogen manuring in an efficient way to prevent and/or cure the abnormality studied.