Dieffenbachia abnormality - Ask Extension
I need your help with an abnormality in a house plant, which I believe is a Dieffenbachia. About a month ago, I noticed several leaves had a serie...
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Dieffenbachia abnormality #927414
Asked April 03, 2026, 11:10 AM EDT
I need your help with an abnormality in a house plant, which I believe is a Dieffenbachia. About a month ago, I noticed several leaves had a series of bumps all in a line on their surface. There is also a sticky substance on both the underside and surface of some leaves. Prior to this discovery, the plant seemed healthy. No new plants have been introduced in their vicinity.
Thank you!
Worcester County Maryland
Expert Response
The leaf looks more like an Aglaonema (they are related to Dieffenbachia), but in this case, the plant's exact ID shouldn't matter much. The rippled texture looks normal in that some environmental conditions (like soil moisture irregularities) can cause leaves to expand unevenly when they are unfurling from the bud. Leaves can't heal or change shape after they have expanded, but we don't see any concerning symptoms associated with that minor disfigurement, and the leaf is functioning normally in terms of being able to photosynthesize and feed the plant.
As for sticky residue, there are a couple possibilities. One is a normal exudate produced by plants in this family, where they may be "extrafloral nectaries" that in nature serve to attract ants and other insects that can help defend the plant against pests. (Essentially, it's like the plant produces tiny amounts of nectar-like liquid in glands that are on parts of the plant that aren't flowers, like pores on the back of the leaf. Ants would get a sugary treat and in exchange they roam over the plant and attack or eat other insects they find.)
Another possibility is that the residue is honeydew, a sugary clear liquid produced by certain sap-sucking insects like aphids, mealybugs, and soft scale. Thrips sometimes create sticky residues due to the sap oozing out from feeding wounds. (Visit the linked pages for image examples and more information.)
Those pests would be visible to the naked eye (although magnification helps) and tend to cluster on the underside of leaves, or in crotches where leaves join the stem. Often, such pests can be largely removed with a strong spray of plain water (such as in a sink or shower) and rubbing them off the plant with your fingers or a paper towel. (Avoid using an alcohol wipe as that can damage leaf tissue.) However, we don't see indications of any of those pests in the photos, but you can inspect that and other leaves (especially on the undersides) to check for insects.
Our suspicion based on the healthy-looking leaves is that the residue is the natural exudate instead, which can also be produced on the leaves of relatives like Philodendron. Occasionally showering houseplants to rinse off the leaves can not only remove accumulated dust (and discourage pests like mites), but also dilute and rinse away sticky residues like the extrafloral nectary liquids.
Miri
As for sticky residue, there are a couple possibilities. One is a normal exudate produced by plants in this family, where they may be "extrafloral nectaries" that in nature serve to attract ants and other insects that can help defend the plant against pests. (Essentially, it's like the plant produces tiny amounts of nectar-like liquid in glands that are on parts of the plant that aren't flowers, like pores on the back of the leaf. Ants would get a sugary treat and in exchange they roam over the plant and attack or eat other insects they find.)
Another possibility is that the residue is honeydew, a sugary clear liquid produced by certain sap-sucking insects like aphids, mealybugs, and soft scale. Thrips sometimes create sticky residues due to the sap oozing out from feeding wounds. (Visit the linked pages for image examples and more information.)
Those pests would be visible to the naked eye (although magnification helps) and tend to cluster on the underside of leaves, or in crotches where leaves join the stem. Often, such pests can be largely removed with a strong spray of plain water (such as in a sink or shower) and rubbing them off the plant with your fingers or a paper towel. (Avoid using an alcohol wipe as that can damage leaf tissue.) However, we don't see indications of any of those pests in the photos, but you can inspect that and other leaves (especially on the undersides) to check for insects.
Our suspicion based on the healthy-looking leaves is that the residue is the natural exudate instead, which can also be produced on the leaves of relatives like Philodendron. Occasionally showering houseplants to rinse off the leaves can not only remove accumulated dust (and discourage pests like mites), but also dilute and rinse away sticky residues like the extrafloral nectary liquids.
Miri
