Herbaceous and woody ornamental plants are prone to root rot when subjected to warm, wet soil conditions. The infection damages the roots, impairing nutrient uptake and causing the plant's health to deteriorate, which can ultimately lead to plant death.

To protect your crops from root rot, it's crucial to ensure a dry, clean growing environment and scout frequently. Furthermore, integrating root rot control products into your management routine can help address current issues and safeguard against future infections.

Know the signs of root rot pathogens

Root rots are caused by a variety of pathogens, including:

Cylindrocladium spp. (Cylindrocladium Stem & Root Rot)

Cylindrocladium is a fungus that causes root and stem rots on many ornamental plants including azaleas, roses and Spathiphyllum, or peace lilies. Affected plants may show vascular browning that extends to approximately 1 inch above the soil line. Root and petiole rot is common on Spathiphyllum, causing yellowing and collapse of lower foliage.

Rhizoctonia solani (Rhizoctonia Crown & Root Rot)

Root rot caused by this pathogen causes wilting, leaf yellowing and often plant death as plants collapse.

Sclerotium rolfsii, Sclerotium spp. (Sclerotium Crown & Root Rot)

The pathogen invades through the roots and lower stem causing the lower leaves to turn yellow, followed by wilting and death of the plant. Sclerotia, the mycelium seen growing on infected stems at or below the soil line, are initially light tan in color, turning dark brown as they age and will persist in plant debris and soil for long periods causing new infections.

Pythium spp. (Pythium Root & Crown Rot)

Infected roots are soft, brown with a water-soaked appearance. The outer portion of the root is easily removed, leaving behind the stringy vascular core of the root.

Incorporate control solutions

To prevent root rot infections in your operation, rotate products labeled for root diseases into your management program. As a drench, Mural^® fungicide (FRAC Groups 11 and 7) moves up the roots and into the foliage to protect new plant growth and inhibit disease progression for better control. Another excellent option is Postiva^™ fungicide (FRAC Groups 3 and 7), powered by ADEPIDYN^® technology, which provides long-lasting protection against the most challenging foliar and soilborne diseases, including Fusarium. Rotating Mural and Postiva offers a strong defense against multiple pathogens while helping delay the development of resistance.

View our fungicide guide to learn more about solutions for root rot control in your operation.

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

© 2025 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^®, GreenCast^®, Mural^®, Postiva^™ and the Syngenta logo are trademarks of a Syngenta Group Company. All other trademarks are property of their respective owners.