Fungicides are an option to help prevent further development on unaffected grass, but will not reverse the factors causing the disease or eliminate the disease. Fungicides treat the symptoms but not the cause of the problem. Rust Turns Lawns Orange Rust can be very common in the late summer to early fall period, especially when the weather is dry. Rust spores can easily be tracked into homes. Lawns White Finally, powdery mildew is a common disease of lawns in shade areas.
Powdery mildew develops primarily on Kentucky bluegrass in the shade.