dieback

noun Plant Pathology.

1. a condition in a plant in which the branches or shoots die from the tip inward, caused by any of several bacteria, fungi, or viruses or by certain environmental conditions.

noun

1. a disease of trees and shrubs characterized by death of the young shoots, which spreads to the larger branches: caused by injury to the roots or attack by bacteria or fungi
2. any similar condition of herbaceous plants

verb die back

3. (intr, adverb) (of plants) to suffer from dieback