Stem canker is a fungal disease that can affect sunflowers. It is important to monitor your sunflowers for symptoms of stem canker so that you can take appropriate measures to control the spread of the disease. Here are some symptoms to look out for:
- Lesions on stems: Stem canker usually causes dark, sunken lesions to form on the stems of sunflowers. These lesions may have a brown or black coloration and can vary in size and shape. The lesions often appear elongated and can girdle the stem, leading to wilting or death of the affected areas.
- Bark splitting: As the disease progresses, the affected stems may exhibit splitting or cracking of the bark along the lesions. This can weaken the stem and further contribute to wilting and plant decline.
- Wilting and stunting: Infected sunflowers may show wilting or drooping of leaves and overall stunted growth. This is due to the blockage of the plant’s vascular system, which hinders the movement of water and nutrients.
- Leaf discoloration: Leaves of sunflowers with stem canker may display yellowing, browning, or necrosis. These symptoms often start near the base of the plant and can progress upward.
- Black pycnidia: In advanced stages of the disease, small, black pustules called pycnidia may appear on the stem lesions. These pycnidia contain fungal spores and contribute to the spread of the disease.
It’s worth noting that symptoms can vary depending on the sunflower variety, the severity of the infection, and environmental conditions. If you suspect stem canker in your sunflowers, it is advisable to consult with a local agricultural extension office, plant pathologist, or an experienced agricultural professional for an accurate diagnosis and appropriate management strategies.
