General term (Latin nékrosis = killing, also necrobiosis) for the death of cells, tissue parts or organ districts in plants as a pathological reaction to certain influences with different causes (in the case of complete death of a plant, one speaks of apoplexy). Necrosis is triggered by damaging influences on the cell. The causes are lack of nutrients and oxygen, toxins, too much salt in the soil, water stress (lack of water), radioactivity, etc. As a result, the cells in the tissue die off, followed mostly by an inflammatory reaction. Depending on the type of tissue and the extent of damage, the necrosis heals completely through regrowth of surviving cells, or the dead tissue part is replaced by a connective tissue scar. Necrosis mainly manifests itself first by a yellow or red to black-brown discolouration of the leaves. Later, necrotic spots (dark pustules) form on the leaves.