Which of the following is NOT a common host for powdery mildew?

Powdery mildew is a fungal disease that affects a wide variety of plants, thriving in conditions with high humidity and moderate temperatures. Common hosts for powdery mildew include many ornamentals, herbs, and vegetables, with some plants being particularly susceptible.

Roses are well-known hosts for powdery mildew, often showing symptoms in areas with poor air circulation and high moisture. Zinnias, being another ornamental plant, can also be affected by powdery mildew, especially under similar environmental conditions. Crape myrtle is frequently noted as susceptible to powdery mildew due to its lush foliage that can trap humidity and create a favorable environment for the fungi.

On the other hand, sunflowers are not typically associated with powdery mildew. While they can be affected by other diseases and pests, their robust structure and growing habits make them less prone to this particular fungal infection. This highlights the resilience of sunflowers compared to the other options listed, establishing them as the correct answer in terms of being a plant less commonly associated with powdery mildew.