The most common pests of aloe plants are sap-sucking pests like aphids, thrips, and spider mites. These can be treated using horticultural oil or insecticidal soap. Moist conditions may lead to fungal diseases such as powdery mildew, root rot, and anthracnose. In this guide, we’re going to cover common aloe plant pests and diseases and highlight some prevention and treatment strategies.
If you see your aloe plant covered in a film of white or gray powder-like substance, powdery mildew may be the cause. This fungal disease impacts a wide variety of plants, including aloe.
While many fungal diseases occur in cool and wet conditions, powdery mildew is more likely to occur during warm periods without rainfall. However, high nighttime humidity does encourage it to occur.
If you notice the disease on only one or two leaves, you can remove the infected material to help prevent its spread.
This fungal disease attacks aloe roots, rendering them soft and mushy. As the roots rot, they may have difficulty taking up water and nutrients.
Therefore, another sign of root rot may be limp, droopy, or wilting aloe leaves.
Root rot is more likely to occur when your aloe plant’s soil is moist or poorly draining. Remember to keep the soil on the drier side and use a potting mix with excellent drainage.
If your aloe plant develops root rot, you may need to trim off the infected roots and repot the plant in fresh potting soil.
If you notice your green aloe plant covered in orange specks or larger bronze lesions, aloe rust is likely to blame. Numerous species of fungi cause this disease.
Over time, the spots may become dark and hard (and the leaves may start curling). While the discoloration is unsightly, it generally will not kill the plant.
Like many fungal diseases, aloe rust is more likely to occur in moist environments. Both high humidity and wet plant leaves can increase the likelihood that aloe will develop this issue.
To help prevent aloe rust, avoid getting the plant’s leaves wet. You should also remove any dead or diseased leaves to improve air circulation and limit the spread of disease.
This is another fungal disease that can attack aloe plants. It is most likely to occur in cool, wet conditions with poor airflow.
Anthracnose leads to dark lesions on aloe leaves. If not treated, the disease can spread throughout the plant.
If you notice your plant is developing anthracnose, ensure you are not watering too often. You should also check the humidity and, if possible, move your plant to a drier location.
As far as treatment goes, you can prune off infected aloe leaves. If your plant is severely infected, you can try spraying neem oil, a copper spray, or a chemical fungicide.
A wide variety of sap-sucking insects attack aloe plants. These include aphids, thrips, scale insects, spider mites, whiteflies, and mealybugs.
Although these pests look different, they all attack aloe plants in a similar manner. First, the plants use their sharp mouthparts to piece an aloe leaf. They then suck the juices out of the plant.
If a large number of these pests attack an aloe plant, the plant may become stunted and weak and display signs of yellowing or brown foliage (or brown spots on your aloe plant leaves). These pests can also spread disease.
Since these pests can rapidly multiply, it’s best to remove them as soon as you notice even a few pests.
Pesticide and Insecticide Options & Solutions
Here are some of the common pesticides used to treat aloe plant pests and diseases.
If you want to control fungal diseases like powdery mildew and aloe rust in an organic matter, copper sprays are your best option. While excess amounts of copper can be toxic, it is a naturally occurring substance.
Pick a pre-mixed product like Bonide Captain Jack’s Copper Fungicide (via Amazon) for the easiest option. Thoroughly spray your aloe plant every one to two weeks to help treat and prevent disease.
These oils are specifically designed to help treat sap-sucking pests like aphids and thrips. They work by suffocating the pests, so thoroughly covering the pests is essential.
Two popular types of horticultural oil are mineral oil and neem oil (via Amazon). You can also use kitchen oils like canola oil and vegetable oil if you’re in a pinch. However, these oils may leave an undesirable coating.
Another organic way to kill soft-bodied pests is by spraying them with insecticidal soap. This soap suffocates the pests, therefore, killing them.
While you can spray these pests with a diluted mixture of dish soap, a soap explicitly designed to kill pests (via Amazon) is your best bet.
While copper sprays often work well against fungal diseases, you can also opt to use a synthetic fungicide spray. These sprays can be used to treat anthracnose and powdery mildew.
A final note, whilst aloe plants offer a host of uses and benefits, the latex layer between an aloe leaf’s skin and flesh is considered toxic, so it’s generally prudent to wear protective gloves when performing these types of plant care activities.
How to Use Pesticides & Insecticides for Aloe Plants
Before you use pesticides, you should see if you can control the pests or diseases through physical, cultural, or biological methods.
For example, you may be able to wipe off aphids with a wet rag rather than spray your aloe plant with insecticides. Similarly, providing your plant with the proper environment may help it fight off diseases.
If you decide you do need to use pesticides, make sure to choose a product that is well-suited to the pest or disease at hand. Read all product information and instructions before applying.
You should also make sure to apply the product at the proper interval.
Managing Pests & Diseases
Preventing pests and diseases is a lot easier than treating them! So keep these tips in mind when caring for your aloe plant.
One aspect of preventing pests and diseases is thoroughly examining any new plant you bring into your home. Check for any pests and signs of disease. You can also place your new plant in a separate room for a week to monitor it.
Another part of preventing pests and diseases is keeping your aloe plant as healthy as possible. After all, a healthy plant is better able to fit off attackers.
Remember that aloe likes well-draining soil, and it only needs to be watered when most of the soil is dry. Avoid overwatering at all costs!
Try to keep the humidity low to prevent fungal diseases. You should also trim away any dead or dying leaves and provide good airflow.
Additionally, make sure you position your aloe plant somewhere warm and bright, ideally with 6 to 8 hours of natural, bright, indirect sunlight daily.
Remember that prevention is the best strategy! However, if you notice any common aloe pests and diseases, you now know what treatment steps to take.
For more, see our in-depth guide to the meaning and symbolism of Aloe plants.