A continuous heavy rusting causes leaf blades to yellow, wither and die. Susceptible species like perennial ryegr-ass may be substantially thinned. Severe rusting can indicate inadequate fertilization, so good fertility management can reduce severity or eliminate it. If fungicides are needed, Daconil 2787, Banner, Bayleton or Fore can be used to protect turf from rust. As the weather cools and more dew forms in the evenings, conditions become ideal for the development of Botrytis blight or gray mold.
Powdery mildew is very common on a number of ornamentals at the present time.
Roses, sycamore, tulip poplar, Exbury azaleas, zinnia, lilac, crepe myrtle, English oak, turf, red osier dogwood, magnolias, and many herbaceous perennials can be infected. It is too late in the season for control and the fungus does not do that much damage. Where control is warranted, early sprays when the fungus is first seen will provide good control. Tar spot and frog-eye leafspot on red maple, can be found. Homeowners with maples especially silver and red may see unusual thick, crusty black splotches on the leaves at this time of thL- year.