Deficiency symptoms: Both vegetative growth and fruit production are severely restricted plants appear pale and spindly. New leaves are small but remain green, whereas the oldest leaves turn yellow and die. The yellowing spreads up the shoot to younger leaves. Yield is reduced and fruit are pale, short and thick.
Correction measure: Side-dress deficient in-ground crops with 20-50 kg N/ac, or apply fortnightly foliar sprays of 2% urea at high volume.
Deficiency symptoms: Potassium deficiency causes yellowing and scorching or older leaves. These symptoms begin at the margins of the leaf and spread between the veins towards its centre. Large areas of tissue around the major veins remain green until the disorder is well advanced. A brown scorch develops in the yellow areas and spreads until the leaf is dry and papery. Potassium from a fertilizer side-dressing will move from the soil surface to the roots only if the soil is very sandy. Potassium fertilizers are therefore best incorporated in the soil before planting. Fertigation or drip feeding can also be used to treat a deficient crop.
Correction measure: Foliar spray of KCl 1% at weekly interval.
Deficiency symptoms: Emerging leaves appear scorched and distorted and may cup downwards because the leaf margins have failed to expand fully. Mature and older leaves are generally unaffected. With a severe deficiency, flowers can abort, and the growing point may die. Fruits from calcium-deficient plants are smaller and tasteless, and may fail to develop normally at the blossom end.
Correction measure: Soil application of gypsum as per gypsum requirement based on soil test report or by foliar spray of CaSO4@ 2% solution in water.
Deficiency symptoms: Magnesium deficiency causes yellowing of older leaves. The symptom begins between the major veins, which retain a narrow green border. A light tan burn will develop in the yellow regions if the deficiency is severe. Fruit yields are reduced.
Correction measure: Incorporate magnetite (300 kg/ac) or dolomite (800 kg/ac) into deficient soils before planting. Fortnightly foliar sprays of MgSO4 (2 kg/100 L) at high volume (500-1000 L/ac).
Deficiency symptoms: Distortion of newer leaves (in severe cases the growing point dies) and the appearance of a broad yellow border at the margins of the oldest leaves. Young fruit can die or abort; abortion rates are high. Stunted development and mottled yellow longitudinal streaks, which develop into corky marking (scurfing) along the skin.
Correction measure: Foliar spray of 0.2% Borax at forthrightly interval. Application of 10 kg borax per hectare to deficient soil before will prevent boron deficiency.
Deficiency symptoms: Iron deficiency causes a uniform pale green chlorosis of the newest leaves; all other leaves remain dark green. Initially, the veins remain green, which gives a net-like pattern. If the deficiency is severe, the minor veins also fade, and the leaves may eventually burn, especially if exposed to strong sunlight. Good drainage and soil aeration favour iron availability. Foliar sprays of iron sulphate (150 g/100 L) can be used to treat symptoms
Correction measure: Foliar spray of 0.5% FeSO4.
Deficiency symptoms: The veins of middle to upper leaves of manganese-deficient plants appear green against the mottled pale green to yellow of the blade.
Correction measure: Spray the foliage with MnSO4 @ 0.1% (100 g/100 L water).
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