Alternaria species

Fungal Disease

Alternaria species

Fungal Disease

Alternaria species

Fungal Disease

Alternaria species

Fungal Disease

Target spot or leaf spot of cauliflower is caused by two closely related fungi, Alternaria brassicae and Alternaria brassicicola. The disease is characterized by circular, target-like spots on leaves and blackening of cauliflower curds. It thrives in warm, humid conditions and can lead to significant crop losses if not managed effectively.

Symptoms

Leaf Spots: Circular spots ranging from mid-brown to black

Target-like appearance with a yellow halo surrounding the sunken center

Curd Damage:Blackening of cauliflower curds in severe infections

Causes and Spread

Temperature Requirements:

A. brassicae: Optimal temperature range of 18-24°C

A. brassicicola: Thrives at 20-30°C

Humidity: High humidity with prolonged leaf wetness facilitates infection

Spread:Carried by wind, water splash, and infected crop residues. Survives on brassica weeds and crop debris

Favorable Conditions

Warm temperatures combined with high humidity.Consistent periods of leaf wetness.

Prevention and Control

Crop Rotation: Avoid continuous brassica cropping

Sanitation: Remove and destroy infected plant residues

Weed Control: Eliminate brassica weeds

Water Management: Avoid overhead irrigation

Plant Spacing: Ensure adequate spacing for air circulation

Fungicide Application: Use appropriate fungicides during favorable conditions

Target spot or leaf spot can significantly impact cauliflower production. Preventive measures, timely monitoring, and effective management practic

es are essential to minimize disease outbreaks and ensure healthy crop yields.