My roses and boxelder trees have sticky (sap) leaves, what is causing this problem?



Aphids.  This is a large group of insects, usually found in considerable numbers on stems, leaves and flowers of many plants, causing leaves to curl under and entire plants to wilt.  Aphid nymphs and adults suck sap from plants and secrete "honeydew", a sugary excretion that attracts other insects (especially ants).  Honeydew provides a good environment for the fungus “sooty mold”, a black, powdery fungus on leaf surfaces. 
Recommended aphid control is: spray off plants with a stiff stream of water, knocking pests to the ground where predators will feed on them, or spray with insecticidal soap.  As a last resort, chemicals such as Neem may be used.  Follow label instructions.

Posted on 13 Jun 2006

Karl Hauptfleisch
Salt Lake Master Gardener

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