The Causes of Sticky Substances on Indoor Grapefruit Plants


Citrus fruits as houseplants are challenging enough without the ordeal of insects that create a sticky substance called "honeydew." Some of these pests present only a nuisance on grapefruit but will inevitably spread to more fragile houseplants.

Indoor grapefruit trees may be all foliage and no fruit.


Sticky "honeydew" is generated by insects that suck juices from plants through narrow snouts. They come inside to afflict citrus houseplants like grapefruit on plants that spend summers out-of-doors, in soil or simply through open doors and windows.


Aphids are green or brown insects less than 1/8 of an inch long. They have two "cornicles" on their backsides to secrete honeydew. Keep plants healthy to discourage colonization.


Roundish red or yellowish female scales are the size of a nail head and attack twigs, leaves and branches. Male scales only live a few hours to mate. Oil sprays are frequently recommended for scale control.


These little waxy-white pests prefer grapefruit. They feed at the base of fruit or on leaves where they contact fruit. Kill mealybug colonies with cotton swabs dipped in alcohol.

White Flies

These tiny moth-like pests rise in clouds from leaves. They have no over-wintering ability and die off unless they have a plant to inhabit. They create yellow-mottled leaves.


Treat plants and soil before bringing them in for the winter. Insecticidal soap, petroleum oil sprays and water dips are common methods for treating honeydew-producing pests.


  • botanical garden

Who Can Help

  • California Red Scale
  • Mealybugs and Whiteflies
  • Aphid Control
Keywords: citrus, houseplants, sticky substance, honeydew, insects

About this Author

Laura Reynolds began writing professionally in 1974. She has worked as a nonfiction author and editor, and as a newspaper editor. Reynolds has been appointed and elected to local offices as well. She has a Bachelor of Science in education from Northern Illinois University.

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