Iron chlorosis - Yellowing or chlorosis of the youngest leaves can result from a lack or deficiency of iron, an important plant nutrient.

Symptoms appear on the youngest leaves first: dark green veins surrounded by yellow or light green areas. Iron chlorosis may be associated with a deficiency of iron in the soil caused by a high soil pH, which makes iron unavailable. Sometimes this problem can be traced to damaged roots that are unable to absorb iron from the soil. Roots may be injured by root rot disease organisms, high nematode populations, or poorly aerated or drained soil. Chelated iron sprays offer quick but temporary results. Determine the real cause of the iron deficiency to correct the problem.