Nutritional Deficiencies/Disorders of Citrus

Nitrogen

Dull green, yellowish, smaller leaves, die back of twigs, thin and bushy appearance of tops with sparse bloom are some of the symptoms of nitrogen deficiency. Deficiency is expressed by light green to yellow foliage over the entire tree. With mild deficiency, foliage will be light green progressing to yellow as conditions intensify. New growth usually emerges pale green in colour, but darkens as foliage expands and hardens. With yellow vein chlorosis, the midribs and lateral veins turn yellow while the rest of the leaf remains a normal green colour.

Correction measure: Foliar sprays urea @ 2% at 15 days interval.

Potassium

The deficiency symptoms of Potassium are

• Slower growth, shedding of leaves at blossom tine, new shoots poorly attached to twig.
• Smaller leaves, twigs die peak, scorching of leaf tips, small brown resinous spots on leaf.
• Small wrinkled spotted leaves.

• Small fruits, thin peel.
• In mandarin – yellowing and bronzing of leaves become twisted, wrinkled and spindy twigs.

Correction measure: Foliar spray of KNO₃ 2% at fortnightly interval. Application of 200g N, 100g P₂O₅ and 200g K₂O / tree/year.

Boron

Deficiency symptoms include

• Premature wilting, water soaked spots on leaves.

• Premature shedding of leaves, bushing appearance curling of leaves, splitting and curling of veins.
• Fruits with gum spots and lumpings, hand abnormal shape and small

Correction measure: Foliar spray of borax @ 0.5%

Copper

Deficiency symptoms include reduced growth and dark green colour of leaves, twin led malformed leaves, new leaves shrivelled and bushy growth

Correction measure: Foliar spray of CuSO₄ each 0.5% at fortnightly interval.

Iron

Thin leaves with interregnal choruses in young leaves. Green tinge at the base of mid rib. Leaf size reduced. Later the leaves become pale or whitish and shed. Die back symptom older leaves remain green, fruits hand, coarse light coloured.

Correction measure: Foliar spray of FeSO₄ @ 0.5% twice at fortnight interval.

Manganese

Fine network of green veins as a light green background on young leaves. Leaf remains fairly green. Dark green irregular bands on mature leaves along the midrib. White spots develop in interregnal area with die back symptom.

Correction measure: Foliar spray of 0.5% MnSO₄ at fortnightly interval.

Zinc

Symptoms include - Irregular and chlorite leaf spots, mottled leaf, small leaves and severe dieback of twigs. The area near midrib and lateral veins remain green. Terminal twigs have narrow small erect leaves. Small, thin skinned fruits.

Correction measure: Foliar spray 2% ZnSO₄ with 1% lime at fortnightly interval.

IPM for Citrus

To know the IPM practices for Citrus, click here.

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