If you find white, woolly or grayish-white deposits on the palm trees, they are usually pests. Powdery mildew, as in other plants, is rare. Since the sap-sucking animals can cause massive damage to the palm tree, you should always treat it with a suitable product.
What is the white coating on my palm tree and how do I combat it?
A white or grayish-white coating on palm trees is usually a sign of pests such as mealybugs or gall mites. To combat them, isolate the palm tree, use a plant protection product or plant protection sticks containing neem oil (€28.00 on Amazon) and provide good care, such as regular spraying with lukewarm, lime-free water and algae juice.
Identify and combat mealybugs
The little animals, also known as mealybugs, reach a length of one to five millimeters. Their bodies are covered with white, woolly hair, which makes the animals look like tiny cotton balls.
Symptoms of infestation
- Initially small, later merging white spots on the fronds.
- The leaves turn yellow and dry up.
- The lice secrete honeydew, which can subsequently cause an infestation with sooty mold fungi (red-brown spots).
Combat
Isolate the palm tree immediately to avoid the spread of the pests. Use a plant protection product containing neem oil (€28.00 on Amazon), which must act directly on the lice. Furthermore, the harmful insects can be combated very well with plant protection sticks that are inserted into the soil. The active ingredients reach the leaves directly via the sap stream, the mealybugs ingest them and die. In the winter garden you can easily control the lice infestation with the larvae of the Australian ladybird.
Cause of gall mites
These often settle on the yucca palm, and more rarely on real palm trees. At just 0.2 millimeters in size, the animals are so small that they are barely visible to the naked eye.
Symptoms of infestation
The pests leave a whitish coating on the leaves that is very reminiscent of powdery mildew. The sucking action creates tiny hairs that give this impression.
Combat
Specialist retailers have various sprays available that, when used correctly, cause the animals to die quickly. In any case, spray not only the top of the leaf, but also the underside of the leaf and the leaf axils, as the pests like to hide here.
Tip
Pest infestations can often be prevented through good care. Spray the palm tree daily with lukewarm, lime-free water. Mix some algae juice into the spray water once a week. This strengthens and strengthens the plant.