Yellow Leaves in Onion

Common Causes

• Nitrogen deficiency — older leaves yellow + droop
• Iron deficiency — young leaves pale
• Downy mildew — yellow lesions with grey spores
• Thrips damage — silvery-yellow streaking

Treatment

Nitrogen: Urea 15kg/acre drip. Downy mildew: Mancozeb 75% WP 2.5g/L. Thrips: Spinosad 0.3mL/L.

Prevention

Avoid water stress, balanced N program, avoid overhead irrigation.

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