Nutrient Management - Growing Organic Orchard Fruits - page 376

Copper (Cu) Deficiency
Symptoms. Copper is not mobile in plants, and deficiency symptoms
usually appear on younger leaves first. The leaves are stunted or mis-
shapen, and the margins may be irregular. Yellowish or white mottling
may appear between the leaf veins. Fruits may be small, poorly
colored, and of poor quality.
Treatment. Seldom a problem in organic orchards where copper fun-
gicides are used to control diseases.
Iron (Fe) Deficiency
Symptoms. Iron deficiency is among the easiest nutritional disorders
to spot. Leaf blades turn yellow to white but the veins remain dark
green. Symptoms appear first on younger leaves and are generally
worse in early spring when soils are cold and wet. Necrotic areas can
develop along the leaf margins and between the veins. New shoots are
stunted and may die back. Flowering and fruiting are decreased.
Treatment. Foliar sprays of approved iron-containing products
provide quick but temporary relief. Follow label directions. Iron
chlorosis is seldom due to Fe being deficient in the soil, and is more of-
ten due to high soil pH, wet soils, cold soils, and/or excess Ca and P. It
is often caused by overirrigation or poor drainage, especially on al-
kaline soils. Ensure that irrigation water is evenly distributed
throughout the field. Drain or do not plant on wet sites. Use sulfur to
lower soil pH to 6.5 on alkaline sites.