Spotty issue for Susans


July 05, 2008|By Ellen Nibali and Jon Traunfeld | Ellen Nibali and Jon Traunfeld,Special to the Sun

My black-eyed Susans have roundish spots on the leaves. How can I prevent this?

We are getting many reports of fungal disease this year because of the wet weather. Septoria is one of several leaf-spot disease possibilities. It has roundish spots with a lighter gray center.

The easiest approach to treating your plants is to pull off infected leaves as soon as you spot them. Thin plants for good air circulation; especially remove excess volunteers. Avoid overhead watering. A sulfur fungicide will help control infection. Like most fungicides, it does not cure current infection but works to prevent new infection.

Ellen Nibali, a horticulture consultant, works at Maryland Cooperative Extension's Home and Garden Information Center, and Jon Traunfeld is the director of the Home and Garden Information Center. Call the center's help line at 800-342-2507.

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