Ring spot

Mycosphaerella brassicicola:

Mycosphaerella brassicicola is a fungal pathogen that causes Blackleg disease in cruciferous crops, including various Brassica species such as cabbage, broccoli, cauliflower, and canola (oilseed rape). Blackleg is a significant concern for these crops, and the disease can result in yield losses if not properly managed.

Symptoms:

1. Lesions on Leaves: The disease typically starts with the appearance of dark lesions on leaves.
2. Lesion Expansion: Lesions can enlarge, coalesce, and cause extensive tissue damage.
3. Stem Cankers: As the disease progresses, it may lead to the formation of cankers on the stems.
4. Plant Wilting: Severe infections can cause wilting and death of the affected plants.

Identification:

1. Leaf and Stem Examination: Inspect leaves and stems for the presence of dark lesions and cankers.
2. Characteristic Symptoms: The characteristic symptoms of Blackleg are distinct and can help differentiate it from other diseases.

Management:

Cultural Practices:

1. Crop Rotation: Practice crop rotation to reduce the risk of disease buildup in the soil.
2. Resistant Varieties: Plant cruciferous varieties that are bred for resistance or tolerance to Blackleg.

Fungicide Application:

1. Foliar Fungicides: Application of fungicides can help manage Blackleg, especially during periods of high disease pressure.
2. Seed Treatment: Treating seeds with fungicides before planting can provide early protection.

Resistant Varieties:

1. Plant Resistant Cruciferous Varieties: Utilize varieties that have been bred for resistance to Mycosphaerella brassicicola.

Sanitation:

1. Remove Infected Residues: Collect and destroy infected plant residues to reduce the overwintering source of the pathogen.

Regular Monitoring:

1. Scouting for Symptoms: Regularly monitor cruciferous crops for early symptoms of Blackleg, especially during conditions conducive to disease development.