Which of the following is a symptom of powdery mildew infection?

A symptom of powdery mildew infection commonly includes the curling of leaves and stunted growth. This fungal disease manifests as a powdery white or gray coating on the leaves, which can disrupt photosynthesis and ultimately inhibit the plant's overall health. As the fungus spreads, it often leads to poor nutrient uptake and water loss, resulting in leaves that curl and growth that is significantly stunted.

While other options may describe various plant issues under different circumstances, they do not specifically align with the typical symptoms associated with powdery mildew. Bright color changes in leaves can indicate nutrient deficiencies or other diseases, excessive blooming might suggest stress or favorable growth conditions, and undamaged root systems do not relate to the visible symptoms of a fungal infection like powdery mildew. Thus, the correct answer effectively captures the characteristic impact of this specific pathogen on a plant's physiological state.