Honeydew is a clear, sticky secretion from a variety of sap-feeding insects (Homoptera Order). Dripping off the insects, cars, benches and other plants below become a sticky mess. Honeydew is often mistaken for tree sap.
Sap-sucking insects feed on the leaves of shrubs and trees. Sap is high in sugar and low in nitrogen. In order to get enough nitrogen, the insects consume too much liquid and sugar. The excess sugar is secreted as a waste product called honeydew. This excess sugar draws insects such as flies, ants, and bees.
Several varieties of insects produce honeydew. Common ones include: aphids, mealybugs, soft scales, leafhoppers, whiteflies and psyllids. Both immature and adult stages of these insects secrete honeydew. They excrete an amount of honeydew several times their body weight.
Honeybees and ants harvest honeydew from sap-feeding insects. Ants use honeydew as an important food source. As a result, ants protect sap-feeding insects from predators. The presence of ants may indicate an infestation of sap-feeding insects. Honeybees process honeydew into a dark, strong-tasting honey.
A black fungus grows on the surface of honeydew. The dark fungal strands looks as if the object is covered with a layer of soot thus the name Sooty Mold. This dark fungus interferes with photosynthesis thus stunting plant growth. Severe coverage can cause premature leaf drop
Control begins with elimination of the honeydew producing insects. Horticultural oils and insecticides can be used to kill the insects. Remove honeydew quickly. Detergent and water combined with a lot of scrubbing will remove honeydew and sooty mold. The longer honeydew is left on patio furniture or vehicles the harder it is to remove.
- University of Illinois Extension: Troubleshooting Cultural Diseases and Insect problems
- University of California: How to Manage Pests in Gardens and Landscapes
- Iowa State University: Houseplant Scale Insects
honeydew removal, black mold honeydew, tree sap honeydew, aphids sap production
About this Author
Lisa Roberts has embarked on a writing career after 10 years in human resources. She holds a bachelor's degree in human resources and marketing from Baylor University. She began writing for eHow in 2009.