Like other plants, the otherwise quite robust yucca palm can of course suffer from various diseases or be attacked by pests. Most of the time the pathogens or animals come from a new houseplant that has already brought them with them and is now happily distributing them to their plant neighbors. For this reason, new acquisitions should always be quarantined first.
Why does the yucca palm have sticky leaves?
Sticky leaves on a yucca palm are often caused by plant lice such as aphids, scale insects or mealybugs. These suck the plant sap and secrete “honeydew,” which causes the sticky spots on the leaves. Effective control can be achieved by washing the affected leaves with water and detergent or using pesticides.
The cause of sticky leaves is usually plant lice
If you notice sticky spots on the leaves of your otherwise he althy Yucca - sometimes the shoots can also be affected - these are usually plant lice such as aphids, scale insects or mealybugs. These usually sit on the undersides of the leaves and suck out the sap from the plant. What ultimately leads to the sticky leaves is the animal excretions called “honeydew”. This sweet goo not only sticks to the leaves, but can even drip onto the ground, leaving spots that are difficult to remove. By the way: Honeydew attracts other pests such as ants or pathogens such as fungi (especially sooty mold!) and should therefore be removed as quickly as possible.
Identifying scale insects and other plant lice
It is a scale insect if you can see tiny, greenish to brown “eggs” on the yucca leaves. The larvae of the animals are found in these cocoons. Mealybugs, on the other hand, are noticeable through white, cotton-like tufts that suddenly spread across the plant. Aphids, on the other hand, can be colored very differently depending on the species and are usually noticeable through black, brown or green dots.
Fight plant lice effectively
If the infestation has not progressed too far, all you need to do is wash the affected leaves with a little water to which you have added a few drops of dishwashing liquid and rapeseed oil. Rub gently to remove the stuck lice and their larvae. Unfortunately, you don't catch all pests the first time, which is why the procedure should be repeated every few days. However, in the case of a severe infestation, the only thing that usually helps is scissors and a pesticide.
Prevent plant lice infestation
Fresh air with sufficient humidity keeps the pests away. Therefore, put the yucca outside in summer and otherwise spray it from time to time with warm water from a sprayer.
Tip
For scale insects or mealybugs, spraying with cold coffee is often successful.
