University of Illinois Extension

University of Illinois Extension

Hort Answers

Fungal Disease

Sooty Mold
Numerous genus and species

Tortise scale crawlers and sooty mold on pine.
Tortise scale crawlers and sooty mold on pine.
3 (1 = rare 5 = annual)
3 (1 = very little damage 5 = plants killed)
These fungi grow mostly on insect honeydew. Therefore they grow on any plant where enough honeydew accumulates. Often more than one fungus may intermingle on the same leaf.

Plants Affected
Sooty mold fungi have black mycelium and grow on insect honeydew. The honeydew is excreted by certain types of scales and aphids. The thickness and black intensity can vary with the individual fungus as well as multiple fungi growing together.

Life Cycle

As long as there is a sufficient amount of honey dew, sooty mold will grow - not only are plants affected but also cars, roofs, walls, patios and so on.

Manage most sooty molds by reducing the insects which produce the honeydew.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic