Chlorosis is a symptom of a plant being nutrient deficient, and therefore
unable to produce adequate amounts of chlorophyll.
The photo on the right shows a plant which has chlorosis caused by iron deficiency.
The plants newest leaves
become more yellow than normal, with the veins on the leaves being the last
part to turn yellow. A plants inability to take up iron is usually the result
of one of two causes. 1) Soil is deficient in iron. 2) Chemistry of the
soil prohibits the uptake of iron. Many plants cannot properly absorb
iron from the soil when it is too alkaline for them or if the soil is
too wet. Severe chlorosis can kill a plant.
Root rot happens when a plants roots are attacked by micro organisms such
as bacteria and fungi. The most common cause of root rot is overwatering.
Severe root rot can kill a plant.
Salt burn is caused by excess salts in the soil. The best way
to prevent salt burn in Phoenix soils is to deep soak the soil.
Early evidence of salt burn is leaf curl, followed by the perimeter
of leaves everywhere on the plant turning brown and drying out. The drying/burning
will start at the tip and procede along the edges to the base. Severely burned leaves will fall off.
Many plants can withstand salty soil and persist for years while other plants will sicken and
eventually die. Excess fertilizer adds salt to the soil, so one should
be very careful when fertilizing salt sensitive plants.
Below is a listing of particularly salt sensitive
Banana (fruit are more sensitive than the plant itself)