Botryosphaeria head blight

Botryosphaeria spp.

Causal Agent: Botryosphaeria is a genus of fungi that includes several species causing canker diseases in a wide range of woody plants, including trees and shrubs. Different species within the genus, such as Botryosphaeria dothidea, can cause similar symptoms.

Symptoms:

  1. Cankers:

    • The formation of sunken cankers on branches, stems, and trunks of infected plants.
    • Cankers may appear discolored and have a dark, necrotic center.

  2. Dieback:

    • Infected branches may experience dieback, leading to a reduction in the plant's overall vigor.

  3. Fruit Rot (in fruit crops):

    • In fruit crops, such as apples, pears, and grapes, Botryosphaeria species can cause fruit rot, resulting in the decay of fruits.

  4. Foliage Symptoms:

    • Wilting, yellowing, or browning of foliage in the affected areas.

Identification:

  1. Cankers:

    • Identification is based on the presence of sunken, discolored cankers on stems and branches.

  2. Fruiting Bodies:

    • The fungi may produce small, dark, pimple-like structures (pycnidia) on the surface of infected bark.

Conditions Favoring Disease:

  1. Wounds and Stress:

    • Infection often occurs through wounds or stressed plant tissues.

  2. Warm and Humid Conditions:

    • Optimal Growth Conditions: These fungi thrive in warm and humid environments.

Management:

  1. Pruning:

    • Prune and remove infected branches, promoting air circulation and reducing disease spread.

  2. Sanitation:

    • Remove and destroy infected plant material, including cankered branches, to minimize inoculum.

  3. Fungicides:

    • Application of fungicides may be considered for managing the disease, especially in high-risk situations.

  4. Stress Reduction:

    • Minimize stress factors, such as drought or excessive pruning, to enhance plant vigor.

Note: Botryosphaeria species are known to be significant pathogens causing canker diseases in various plant species. Effective disease management involves a combination of cultural practices, pruning, and, in some cases, chemical control.