What Is the Sticky Liquid Oozing Out of Trees?

Date April 07, 2023

Author TreeNewal Staff

If you spend a lot of time in nature, chances are you already had an encounter with a tree dropping a gummy goop that looks just like sap. However, that sticky liquid oozing out of trees is actually insect waste, and it’s called honeydew. Here at TreeNewal, we want to help you prevent and protect your trees, so in today’s post, we’re discussing insects, honeydew, and the most common ways to deal with this infestation.

What Is Honeydew?

Image via Flickr by functoruser

Honeydew is a clear to brown, sticky, sugary liquid found on trees that are infested with aphids or scale insects. These insects thrive in low-oxygen environments, and as they feed on the tree juices, sap and methane gas build up pressure inside the tree. The pressure eventually forces the honeydew out through the weakest part of the tree. Once the slimy liquid is outside, ants feed on it.

How Can Honeydew Affect Trees?

Depending on the type of insect sucking the sap and the severity of the infestation, honeydew can have mild to severe effects on a tree. Sooty mold, for example, is a mild effect that doesn’t cause much damage but can be annoying. Other effects of honeydew include wilting, curling, leaf distortion, and fruit drop.

How To Prevent It

Once a tree is infested with aphids or scale, it is very difficult to completely eradicate the pest. In fact, with proper care, infested trees are more likely to develop resistance and live with the condition for years. While some trees are more susceptible to aphid infestation than others, preventive measures can help keep your tree healthy.
To prevent aphid infestation, you need to consider four elements: maintenance, weather, tree type, and tree health. As mentioned above, some trees, such as tulip trees, lindens, poplars, and weeping willows, are more susceptible to this type of infestation. If you work with an arboriculture company like us, we can help you take care of your plants and prevent insects from sucking the sap out of your tree.

How To Deal with Honeydew

Getting rid of zillions of insects is a really tough task, especially when we’re talking about the ones that cause honeydew. First, you should know that beneficial insects like ladybugs can eat the pest, so they’re your friends. However, if there are ants around, they will protect the insects that make the sticky liquid they love. In other words, you need to get rid of the ants before you try anything else.
Spraying the tree with soapy water is a smart solution, but you must be aware that you will need to repeat the process a week later to kill the offspring. Alternatively, you can use dormant oil, another effective and organic pest control. Whatever you do, try to avoid most insecticides, as they are better at killing beneficial insects than the pest itself.
If one of your trees is oozing a sticky liquid and you’d like an ISA-certified arborist to help, contact TreeNewal and we’ll help you restore your tree.