Iron
Iron is needed for chlorophyll formation, plant respiration and the formation of some proteins.
Identification
- Symptoms are very similar to manganese deficiency,
- Deficiency occurs more frequently when pH is high and can be caused by high levels of lime (lime-induced chlorosis),
- Symptoms appear on the young leaves first,
- Leaves turn yellow between the veins, but the veins will remain green except in extreme cases,
- Often symptoms are seen in only one area of the plant,
- Shoots may die back if iron deficiency is not corrected.
Often Confused With
Chemical:
- herbicides such as triazines (simazine, atrazine); ureas (diuron, linuron), uracil (terbacil, bromacil); dichlobenil, paraquat, fluazifop-butyl, oxadiazon,
- high -very levels of phosphorus may reduce iron uptake,
- excessive soil liming.
Disease:
- virus diseases
Insects:
- aphids,
- leafhoppers,
- mites,
- plant bugs.
Mechanical:
- damaged stem or trunk.
Soil & planting conditions:
- calcareous soils, mineral soil pH > 6.5,
- excessive levels of phosphorus, copper, zinc or manganese may induce deficiency,
- over fertilization or salt damage,
- cool, wet or compacted soils resulting in reduced root growth and poor uptake,
- waterlogging,
- poor soil aeration.
Weather:
- excessive soil moisture and cold, wet spring,
- hot, dry summer.
Scouting Notes
Factors associated with iron deficiency include soils with high lime content (and therefore high pH), and gross imbalances with other micronutrients like molybdenum, copper or manganese.