Chilli yellow-leaf disorder (pandaaku)

The 'yellow-leaf' complex in chilli — known in Telugu as pandaaku — is rarely a single disease. It combines zinc, iron, manganese and boron micronutrient deficiencies with secondary fungal leaf-spot infections and sucking-pest-induced chlorosis. The correct diagnosis is therefore typically a deficiency syndrome rather than an infectious disease.

Identification and symptoms

TNAU notes that chilli has a particularly high zinc requirement; deficiency produces interveinal chlorosis, narrowed distorted leaves and a 'little-leaf' rosette habit. Iron deficiency produces interveinal chlorosis on new growth with the veins remaining green. Manganese and boron deficiencies, and persistent sucking-pest feeding (Pest Sucking Pests Chilli), can produce a similar generalised yellowing.

Host crops / Life cycle

The disorder is not infectious. Its components are physiological (Zn, Fe, Mn, B deficiency), abiotic (high pH, alkaline soils) and biotic (whitefly, aphid and thrips feeding; secondary leaf-spot fungi).

Damage and economic impact

Unmanaged pandaaku causes loss of photosynthetic area, narrowed and rosetted canopies and substantial reduction in pod set and weight.

Management (cultural, biological, chemical)

Foliar correction — ZnSO4 0.5%, FeSO4 0.5%, borax 0.2% and a balanced micronutrient mixture
Soil correction — balanced NPK and micronutrient application via the staged fertiliser schedule (Practice Chilli Fertilizer Schedule)
Pest control — sucking-pest management (Pest Sucking Pests Chilli) where insect-induced chlorosis is suspected
Fungicide pairing — mancozeb or pyraclostrobin where leaf-spot is co-occurring

Because boron is also a major driver of flower retention (Disorder Chilli Flower Bud Drop), the corrective sprays often serve a dual role.

Practice Chilli Fertilizer Schedule, Disorder Chilli Flower Bud Drop, Pest Sucking Pests Chilli

References

Nutrient Deficiency Symptoms of Plants. TNAU Agritech.
Micronutrients for horticultural crops. TNAU Agritech.