Kentia palms (Howea forsteriana) are popular indoor palm trees known for their fabulous fronds. So, it can be upsetting when pests and diseases start attacking your Kentia palm. In this article, I’ll look at ten common Kentia palm pests and diseases and how to deal with them.
10 Common Kentia Palm Pests and Diseases:
Aphids are small black or green insects that feed on the sap of Kentia palms growing outdoors. Aphids usually congregate in large numbers along stems or on the undersides of leaves.
These insects produce sticky deposits of honeydew that can turn into sooty, black mold. Other symptoms include distorted or stunted growth.
Use horticultural oils or insecticidal soap to eliminate aphids. You can also blast your Kentia palm with a hose to dislodge large numbers of aphids at once.
2) Fungus Gnats
Fungus gnats are annoying black or brown flies that lay their eggs in moist soils. While adults won’t harm your plant, the larvae consume roots or stems once they hatch. This can stunt your Kentia palm’s growth.
I typically use sticky traps or bottle tops filled with almond oil to catch adult gnats. I remove the larvae by replacing the top few inches of soil with a mix of coco coir and coarse sand.
Mealybugs are small, oval-shaped insects that feed on plant sap. Mealybugs typically thrive in the warm, humid conditions that Kentia palms need. The easiest way to spot a mealybug infestation is to look for deposits of fluffy white wax on your palm’s stems and leaves.
Other symptoms of mealybug infestations include stunted growth and deposits of honeydew or sooty black mold. Use insecticidal soap, horticultural oils, or swabs of isopropyl alcohol to remove mealybugs.
4) Scale Insects
Scale insects are another type of sap-sucking pest that can attack Kentia palms. Scale insects have either armored or soft shells but are hard to detect until they start causing problems.
If your palm is infested with scale insects, you may notice stunted growth, and drooping or yellowing leaves. Scale insects can also produce sticky deposits of honeydew that can turn into black, sooty mold. Use insecticidal soap or horticultural oils to get rid of scale insects.
5) Spider Mites
Spider mites are small, sap-sucking arachnids that thrive in warm, dry conditions. These pests are named after the protective webbing that they produce to protect their eggs. This webbing is one of the tell-tale signs of a spider mite infestation.
Other symptoms of spider mite infestations include stunted growth and brown or yellow mottling on your Kentia palm’s fronds. The easiest way to eliminate spider mites is to use horticultural oils or insecticidal soap.
Adult thrips are slender, yellowish-brown insects that consume plant sap and can fly to other plants. Young thrips are paler in color than the adults and don’t have wings. Thrips typically target young, vulnerable leaves of your Kentia palm.
As they feed, thrips cause leaves to become discolored, creating silvery-green patches on the leaves. Stunted growth is another symptom of a thrip infestation. Use insecticidal soap, horticultural oils, or sticky traps to catch and eliminate thrips.
7) Botrytis Blight
Also known as gray mold, botrytis blight is a fungal disease that can affect Kentia palms. Fungi from the Botrytis genus cause this disease. The main symptom of botrytis blight is gray mold on the leaves.
Palms infected with botrytis blight may also have brown or misshapen leaves covered in brown spots. Botrytis blight is more common in cool, humid conditions. Remove any infected foliage and use organic copper fungicides to treat botrytis blight.
8) Leaf Spot Diseases
Leaf spot diseases are common fungal infections that are usually caused by Fusarium fungi. Infected Kentia palm fronds display dark brown spots that are ringed with yellow. The tissue within the spots will appear dry and papery.
Once a frond is infected with a leaf spot disease, it will not recover. Remove infected fronds at the base of the stem. You can also use organic copper fungicides to treat leaf spot diseases.
9) Powdery Mildew
Many gardeners will be familiar with powdery mildew. This common fungal disease thrives when the days are warm and the nights are cold. Powdery mildew is named after the powdery white patches that develop on infected leaves.
Other symptoms of powdery mildew disease include curling or yellowing leaves that fall off. Remove any infected leaves at the base of the stem and use organic copper fungicides to treat powdery mildew.
10) Root Rot
Root rot is a fungal disease that develops in waterlogged soils that drain poorly. Root rot can also be caused by overwatering. The main symptoms of root rot include drooping or yellowing leaves and brown, mushy, or smelly roots.
To treat root rot, remove your Kentia palm from its pot and trim off any rotten roots. Repot your palm into a loose, well-draining soil mix. I usually mix some coco coir with some perlite or coarse sand.
Pesticide and Insecticide Options & Solutions
Horticultural oils are a common way of dealing with houseplant pests. Canola oil and neem oil (via Amazon) are two of the most common horticultural oils. These oils work by suffocating pests like aphids and mealybugs. However, some plants can be sensitive to horticultural oils, so try not to use them too frequently during the growing season.
Another way of eliminating Kentia palm pests is to use insecticidal soap. Like horticultural oils, insecticidal soaps work by desiccating and suffocating pests. Try this fantastic insecticidal soap from Bonide. You could also mix some dish soap and warm water to create a homemade alternative.
Sticky traps are another easy way to get rid of fungus gnats and other pests. These traps catch adult fungus gnats, preventing them from laying more eggs. You can pick up some sticky traps from homeware or garden stores.
Fungicides are the easiest way to treat Kentia palm diseases and fungal infections. If you can, use organic copper fungicides, such as this one from Bonide, rather than synthetic ones. Synthetic fungicides can harm beneficial soil organisms. Always follow the instructions and recommended doses detailed on the packet.
Managing Pests and Diseases
While insecticidal soap and fungicides work well, prevention is always the best cure. Providing the right growing conditions helps your Kentia palm resist diseases and pests.
Palms thrive in bright, indirect light but can tolerate some shade. Keep Kentia palms away from direct sunlight, especially during the afternoon. Water whenever the top two inches of soil feel dry to prevent overwatering and root rot.
These beautiful palms grow best in well-draining soils. I like to use a mix of coco coir, houseplant potting mix, and coarse sand or perlite. Give your palm plenty of space away from other plants to limit the spread of diseases and pests.
For more, see our in-depth Kentia palm plant care guide.
Although Kentia palms are easy to grow, they can be vulnerable to pests and diseases. Common Kentia palm pests and diseases include aphids, fungus gnats, mealybugs, powdery mildew, and root rot. Tackle fungal diseases using organic copper fungicides. Eliminate pests using horticultural oils, insecticidal soap, or sticky traps.