This disease also known as web blight is primarily seen during warmer months when high temperatures coincides with high moisture.

The pathogen is soil borne. Yellowing of the leaves followed by brown lesion development on hydrangea is the initial symptom of the disease. The disease is especially severe when plants are grown together.

Browning of the stem is a very common symptom for this disease which leads to girdling and complete death of the top of the plant. Brown mycelium (web-like) can be seen growing on infected leaves and stem. Water-soaking on the leaves can be seen on the infected plants.

Concentric ring-like pattern can also be noticed on the leaves.

Brown, irregular-shaped lesions can be seen on the leaves. The disease can progress in a matter of a few days. The brown lesions can become very large and can cover the entire surface of the leaf in case of severe infection.