What type of disease is caused by a fungus that produces asexual spores, typically presenting ulcer-like areas on the host?

The type of disease characterized by a fungus that produces asexual spores and typically presents ulcer-like areas on the host is anthracnose. This disease affects a variety of plants, including many crops and ornamental species. Anthracnose is caused by a group of fungi that can cause symptoms such as leaf spots, blights, and stem lesions. The distinctive ulcer-like areas are associated with the way the fungus invades and damages the tissue of the host plant.

In contrast to anthracnose, powdery mildew primarily presents as a white, powdery fungal growth on the surface of leaves and does not usually create ulcer-like structures. Dollar spot is a common disease in turfgrasses characterized by small, circular patches of dead or dying grass rather than ulcer-like areas. Black spot is another fungal disease, particularly notable in roses, recognized by dark spots on leaves but typically does not form ulcerations. Thus, anthracnose is the most accurate choice given its symptoms and life cycle related to asexual spore production.