Mycosphaerella brassicicola

Fungal Disease

Mycosphaerella brassicicola

Fungal Disease

Ringspot disease is a fungal infection affecting brassica crops, including Brussels sprouts, cabbage, and cauliflower. It thrives in areas with overlapping crops and is particularly severe in wet conditions (16-20°C).

Key Points

• Symptoms:

  • Light brown to grey spots with a yellow halo.
  • Spots are angular (up to 20mm) and often follow leaf veins.
  • Tiny black fruiting bodies form in concentric rings, giving the disease its name.
  • Affects older leaves and sometimes seedlings.
  • Severe infection leads to yellowing, leaf drop, and reduced growth.

• Spread:

  • Short-distance spread via water splash, wind, and rain.
  • Long-distance spread through infected seeds.

• Impact on Crops:

  • Can make cabbage heads unsaleable.
  • Does not harm cauliflower curds or broccoli heads.
  • Severe infection delays harvest and reduces yield.

• Differentiation from Alternaria:

  • Ringspot lesions are grey with black pinhead dots in rings.
  • Alternaria spots lack the distinct concentric pattern.

Understanding ringspot disease is crucial for managing its spread and protecting brassica crops from significant losses.