Evergreen articles

Yellow blemishes on leaves are called. Chlorosis = yellowing of the leaves due to insufficient production of Chlorophyll. Like Anthracnose, Chlorosis is not a Pathogen, but a sign of ageing, pest attack, nutrient deficiency, too much sunlight, fungal and/or viral infection. Nutrients are mobile and with age or when nutrien supply from the soil is limited and young leaves (growth) need them, translocate from older to new leaves (new growth) causing older leaves to turn yellow (Chlorosis dues to aging process); Nitrogen, phosphorus, potasium and magnesium deficiency can cause Chlorosis (Chlorosis dues to Nytrien deficiency). Sun can yellow leave edged and tips. Sap-sucking insects also cause chlorosis (create yellow rings around the point of entry). Fungi and Virus also cause chlorisis (Chlorotic Ringspot Virus, etc). Bacteria are predominantly involved in the decomposition of leaves and/or stems (ROT) and do not normally cause chlorosis.

There are TWO names for black blemishes on leaves or stems: Anthracnose and Necrosis. Anthracnose is caused by Pathogens; Necrosis is caused by other Natural means. Necrosis is a Greek word and derives from the word Nekros = Death. Necrosis can be partial, a few blemishes here and there, or total, the whole leave dead (Black or Brown).