Nutritional Deficiencies of Grapes

Nitrogen

• Overall reduction in growth.
• Leaves become uniformly light-green or yellow. Reddening of petiole
• Berries may be small

• Soil application of urea @ 20-60 Kg/acre
• Foliar spray of urea (0.3 – 0.5%) 1- 4 times along the growing season , depending on the deficiency severity.

Potassium

• Starts as yellowing (white varieties) or bronze-reddening (red varieties) of olderleaf margins.
• As the deficiency worsens, leaf margins become necrotic and curl upwards and inter-vein alchlorosis develops.
• Berry set can be poor.

• Soil application of 200- 320 Kg K₂O/acre for 2-3 years
• Foliar sprays of sulphate of potash (0.4 -1%), 3-4 times every 15 d before and after flowering.
• Other commercial fertilizers containing K can be used

Magnesium

• Bright yellow (white varieties) or red (red varieties) wedge-shaped areas extend inwards between the veins on older leaves.
• When severe, necrosis extends inwards from the leaf margins.
• Fruit cluster stem necrosis and berry withering

• Soil application of 20-40 Kg MgO/acre
• Foliar application of Magnesium sulphte (2%if MgO =32% or if MgO = 16%) or magnesium chloride /nitrate (1-1.5%) 3-6 times every week, beginning from fruit set
• Sprays against stem necrosis by magnesium sulphate (as above).

Phosphorus

• Vines may have stunted shoots and fruitfulness is likely to be poor.
• Appearance of red dots on basal leaves, especially on the mid or terminal lobes and at first distant from secondary veins.
• The red dots, at first randomly distributed, later line up at right angles to the secondary veins and form dark red bars, which coalesce into islands between green veins.

• Apply ammonium mono phosphate as an N source (11-52-0).

Sulphur

• Reddening of young leaves. Red dots near the edges of adults leaves. Red dots may coalesce later into red bars at right angles to the vein leaves can drop
• Reduced growth lignification is impaired
• Small and loose cluster, due to reduced fruit set

• Soil application of 20-40 Kg/acre P₂O₅

Boron

• Shoot tip death and short internodes, resulting in shoots with a zigzag appearance.
• Yellowing or reddening dots rolling down, corrugation and odd shapes in young leaves
• Fruit set is often poor and bunches often have „hen and chicken‟ berries
• Browning of hypodermal cells and breaking of berry

• Soil application of borax(Sodium tetraborate) 12-32 Kg/acre
• Foliar application of solubor(20.5%B),0.25% 3 times every 15 days ,beginning from 5^th -6^th leaf development stage.

Iron

• Young leaves show interveinalchlorosis.
• When severe, leaves are likely to be very pale with necrotic blotches. Shoots are likely to be stunted in their growth.
• Loose cluster shot berries

• Soil application of Fe-EDTA or foliar application of Ferrous Sulphate (250g/100 litre water) + citric acid (50g) + liquid detergent

Manganese

• Stunted growth
• Interveinal chlorosis or reddening of adults leaves. mosaic like arrangement of yellow /red spots, bordered by the smallest green veins
• Delay of berry ripening

• Foliar sprays of manganese sulphate (0.2 -0.5%) , 3 times, one before and two after flowering
• Foliar sprays of Manganese chelates.

Zinc

• Short internodes, resulting in shoots with a zigzag appearance
• Shoot tips have small upward curling of leaves.
• Mottled, light coloured interveinal colouring on leaves. Small, poorly developed bunches with hen and chicken berries.

• Soil application borax (sodium tertaborate) 12-16 Kg/acre
• Foliar sprays of zinc sulphate (0.5 -1.0%) neutralized with calcium carbonate,3 weeks before flowering

IPM for Grapes

To know the IPM practices for Grapes, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage