Combat Foliar Diseases with a Disease Control Program

Even as we move into fall months, high temperatures and humidity can linger, so it is still important to monitor closely for foliar diseases. Although most pathogens do not cause plant mortality, symptoms can greatly reduce the appearance and salability of infected plants.

Leaf spot pathogens to watch for include Alternaria spp., Cercospora spp., Colletotrichum spp., Myrothecium spp., Entomosporium spp. and Septoria spp., with susceptibility to these agents varying by the host plant. Leaf spots can vary by shape and size but tend to have similar characteristics such as a rounded appearance, distinct margins and a colored border. When scouting for symptoms of disease, be sure to inspect the foliage in the lower and interior canopy of the plant.

Colletotrichum spp. on Euonymus. Syngenta photo, Rechcigl.

Other fungal diseases such as Botrytis and powdery and downy mildews can persist into the fall as well. These diseases produce masses of fuzzy spores directly on the infected tissue. Infections by Botrytis cinerea tend to be more problematic on tender new growth and blooms.

Botrytis sporulation on Gerbera daisy. Syngenta photo, 2016.

Establish a Strong Rotation Program

A solid fungicide rotation program should incorporate two to three products with systemic and contact or translaminar activity, which will maximize their strengths and leverage their different modes of action when they are most beneficial. This will also help mitigate resistance development. Recommended products for a foliar disease agronomic program include Postiva™, Mural®, Palladium® and Daconil Ultrex® fungicides.

Postiva, the latest ornamental disease control solution from Syngenta, is powered by ADEPIDYN® technology and two modes of action to provide reliable control of a variety of diseases, including leaf spots caused by Anthracnose, Alternaria, Cercospora and Septoria spp. pathogens.

Learn more about building a foliar disease control program for your operation here to finish the season strong.

All photos are either the property of Syngenta or are used with permission.

© 2023 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. ADEPIDYN®, Daconil Ultrex®, Mural®, Palladium®, Postiva™ and the Syngenta logo are trademarks of a Syngenta Group Company.

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