Pest of the Month January 2010 – Sooty Mold

  • Hosts:  Any plant that hosts phloem-feeding insects and has honeydew on it
  • Range: Throughout the world’s temperate and tropical regions
  • Symptoms:  A black, non-parasitic superficial growth on plant surfaces that can be completely rubbed off with your fingers to reveal healthy plant tissue
  • Spread through: airborne sooty mold spores
  • Control: management is only warranted when the mold affects the aesthetic value of fruits or landscapes.  The best way to control sooty mold is to eliminate their sugary food supply by controlling phloem-feeding insects on foliage.  Controlling the pests may also require controlling the ants that tend and protect them.

Source: Sooty Mold, Dr. Scot Nelson, University of Hawai’i at Manoa College of Tropical Agriculture and Human Resources Cooperative Extension Service Plant Disease PD-52, October 2008

Sooty mold on ixora. Photo by Carol Kwan.