Leaf spot Septoria
Septoria chrysanthemi
Also Known As - Septoria leaf spotWhat is Leaf spot Septoria (Septoria chrysanthemi)?
Septoria leaf spot, also known as Septoria blight, is a fungal disease that affects a wide range of plants. The disease is caused by various species of the Septoria genus, with Septoria chrysanthemi being a common culprit. Symptoms of Septoria leaf spot on chrysanthemum leaves typically appear as light tan to gray lesions, which are often circular or irregularly shaped. These lesions are usually surrounded by a distinctive purple margin.
How does Leaf spot Septoria (Septoria chrysanthemi) occur?
Septoria leaf spot (Septoria blight) spreads through spores produced in fruiting bodies (pycnidia) within lesions. Rain/irrigation causes spore release, splashing onto nearby foliage. Wind can carry spores short distances, and human activities, like moving through wet foliage, unintentionally spread them. Infected material can introduce the disease to new areas. It's severe in consistently wet, humid regions.
Symptoms
1 - Impact on Plants
• Septoria leaf spot can severely damage plants. Lesions on the leaves cause defoliation, weakening overall health and photosynthesis. • Severe infections result in stunted growth, reduced flowers, and potential plant death, especially with recurring infections. • It can affect the aesthetics of plants, particularly in ornamental gardens and landscapes. Severe defoliation can impact overall appearance.
Solutions
1 - Preventions
1. Choose disease-resistant varieties to minimize the risk of infection. 2. Maintain good garden hygiene by removing and destroying infected plant material, including fallen leaves. This helps reduce the source of fungal spores. 3. Avoid overhead irrigation and water at the base of plants to keep foliage dry. Watering in the morning allows time for leaves to dry before evening. 4. Provide sufficient spacing between plants to promote air circulation and reduce humidity. 5. Rotate susceptible plants with unrelated species to disrupt disease cycles and reduce pathogen buildup in the soil.
3 - Chemical Control
There are several fungicides available for the control of Septoria leaf spot, including azoxystrobin (Heritage, Quadris), myclobutanil (Immunox, Eagle), chlorothalonil (Daconil, Bravo), thiophanate-methyl (Cleary's 3336, Topsin M), propiconazole (Banner, Fungonil), and mancozeb (Manzate, Dithane). It's important to carefully read and follow the label instructions of the specific fungicide product chosen.
