Georgia Pesticide Applicators Practice Exam

Powdery mildew on crape myrtles can be managed by several methods except:

1. Regular pruning

2. Using resistant varieties

3. Thatch should be at least 2 inches thick to keep soil cool

4. Applying fungicides

The correct answer is: Thatch should be at least 2 inches thick to keep soil cool

The management of powdery mildew on crape myrtles involves various methods that target the conditions conducive to the disease's development. Regular pruning is effective as it increases air circulation and reduces humidity around the plant, both of which help prevent the growth of the fungus. Using resistant varieties is also a proactive approach, as these plants have genetic traits that make them less susceptible to infections. Applying fungicides represents a direct approach to managing an existing powdery mildew infection by targeting the fungal spores and preventing their spread. This method is especially useful when the disease has been clearly identified and requires immediate action. In contrast, maintaining thatch at a thickness of at least 2 inches does not play a significant role in managing powdery mildew. Thatch primarily relates to lawn care and soil temperature regulation rather than directly influencing the conditions that contribute to fungal growth on crape myrtles. Therefore, this option does not align with effective management strategies for powdery mildew.