Succulents and cacti stand out for being resistant and low-maintenance plants, Even for those less experienced in gardening. However, it's crucial to understand that they are not immune to diseases and pests. In this extensive article, you'll learn more about them. The most common diseases of succulents, the most common pests, and how to prevent and treat them. to keep your plants healthy and attractive for years.
Why do succulents get sick?
Succulents store water in leaves, stems and roots., which allows them to survive in extreme drought conditions. However, this same natural adaptation also makes them susceptible to Problems caused by excess water, high humidity and insufficient ventilation.Therefore, Inadequate watering, a poorly draining substrate or overcrowding They can trigger fungal or bacterial diseases, as well as facilitate the attack of different pests.
Therefore, although They require less care than other indoor plants, it is essential to know the threats and symptoms that may occur to act in time and avoid irreversible damage.
Most common succulent diseases and how to recognize them
- Root and stem rot: Usually caused by fungi such as Rhizoctonia, Fusarium, Pythium, or Phytophthora. It manifests as soft, brown roots, a softened stem base, and sometimes an unpleasant odor. It is common in waterlogged or poorly drained soils.
- Bacterial diseases (Example: Erwinia)This type of infection produces soft, moist stems with a rotten odor. The leaves show dark, yellow, or brown spots. The agent usually enters through wounds or cuts.
- Powdery mildew: Identifiable by the presence of a whitish powder on leaves and stemsIt spreads in environments with high humidity and poor ventilation.
- Fungal leaf spotsPathogens such as Alternaria, Botrytis, Cladosporium, Bipolaris, Colletotrichum and Cercospora cause circular lesions, spots, or discolorations on leavesIn severe cases, these spots turn black, dark brown, or even have reddish edges.
- Neck rotThe area just above the root softens and rots, quickly affecting the entire plant. Caused by excess moisture, overly compacted substrates, and insufficient ventilation.
- Botrytis (gray mold): It is characterized by the appearance of a grayish layer of spores on leaves or flowers in humid environments with little air movement.
- Verticillium: Causes yellowing, wilting of leaves and general decline, due to the interruption of sap ducts by the fungus.
- Edema: Physiological changes due to excessive water absorption. Leaf cells swell, blisters or translucent spots appear, and the plant may show slow growth or appear dull.
- RoyaSmall orange or brown spots on the underside of leaves. It is less common, but can affect collections in humid, temperate environments.
These symptoms can easily be confused with water shortages, sunburn, or cold damage. Therefore, periodic observation and early diagnosis are key to maintaining the health of your collection.
Common pests in succulents and cacti
- Aphids: Tiny green, black, or yellow insects that suck sap from young stems and leaves. They produce a sticky substance (honeydew) that attracts ants and facilitates the appearance of black fungus.
- Cottony mealybug: It is observed as small white masses on the underside of leaves, in folds, and in hard-to-reach areas. It feeds on the sap and quickly weakens the plant.
- sowbug: It prefers parts close to the substrate and roots. Its presence is revealed by Leaves eaten at ground level and roots attacked, especially in young shoots.
- Red spider and mites: They are practically invisible to the naked eye. They are detected by yellowish spots, fine cobwebs on the underside of the leaves and a dull appearanceThey proliferate with heat and dry environments.
- Nematodes: Microscopic worms present in the substrate that They damage roots and cause wilting or slow growthThey usually appear in poorly drained soils with decomposing organic remains.
- Slugs and snails: They mainly attack succulents outdoors, leaving holes in leaves and stemsThey prefer humid and shady environments.
Early detection is essential, since these pests reproduce rapidly and can affect entire collections in a short time.
How to prevent diseases and pests in succulents
- Take care of the hygiene of the environment: Remove dry or fallen leaves, check that the substrate is free of debris, and keep the pots clean.
- Isolate the affected: When you detect a diseased or infested plant, separate it from the rest to prevent spread.
- Control humidity and irrigation: Water only when the substrate is dry and use specific mixtures for succulents and cacti. Avoid waterlogging and use pots with drainage holes.
- adequate ventilationMaintain a constant and adequate airflow. If the plants are indoors, ventilate the space regularly.
- Inspect periodically: Look at the underside of the leaves for wrinkles, stains, or the presence of sticky or cottony substances.
These best practices drastically reduce the likelihood of infection and pests, and increase the longevity and vigor of your plants.
Key symptoms to detect problems in succulents
- Soft or rotten stem
- Loss of green color, dry or empty leaves
- Discolored, yellowish, or brown-spotted leaves
- Excessive wrinkling or wilting
- Slow or deformed growth
- Visible presence of insects: mealybugs, aphids or other pests
- Appearance of cobwebs or sticky secretions
These clues will allow you quickly diagnose a possible disease or infestation and take appropriate measures as soon as possible.
Treatments and remedies for diseases and pests in succulents
Fungal and bacterial diseases:
- Remove the affected parts: Use sterilized scissors or knives to remove damaged leaves and stems.
- Let wounds dry: Place the plant in a dry, well-ventilated area to heal before replanting.
- Apply specific fungicides: In cases of fungi such as Rhizoctonia, Fusarium, Botrytis, or mildew, use commercial products following the manufacturer's instructions. Alternatively, you can use natural remedies such as diluted hydrogen peroxide (1 part 3% hydrogen peroxide to 2 parts water).
- Change the substrate: Always transplant the succulent to a new, dry and well-aerated substrate.
Pest control:
- Micronized diatomaceous earthEffective against mealybugs, aphids, and other insects. Sprinkle or dilute in water and spray the plant, focusing on affected areas.
- Isopropyl alcohol: Diluted in water, applied with a spray bottle or cotton on pests, it kills most succulents quickly and without damaging them.
- Neem oil: It's a natural insecticide that also works against fungi. Mix a few drops in water and spray the plant. Test a small area before treating the entire plant.
- Manual cleaning: Use a damp cloth or gentle pressure water to remove visible pests.
- Commercial insecticidesIf the infestation is severe, consult with specialists at your nursery to choose a safe and effective product.
For snails and slugs: Remove by hand, use traps (such as beer saucers), and keep the area dry and free of plant debris.
Key tips to keep your succulents healthy
- Always use specific substrates for succulents, with elements such as perlite, coarse sand or gravel. that facilitate drainage.
- Maintain a watering schedule adapted to the season; water less in winter and more during hot periods, but only when the substrate is dry.
- Do not wet the leaves when watering and avoid direct spraying.
- Disinfect tools before pruning or transplanting to prevent the transmission of pathogenic spores.
- Provide plants with sufficient light, avoiding excessive direct sunlight on sensitive species.
Some well-cared for succulents Not only do they look more beautiful, but they're also much more resistant to diseases and pests. Prevention and observation are your best allies.
Although succulents and cacti are known for their extraordinary resistance and adaptability, can be seriously affected if growing conditions are not optimal or if preventative treatments against pests and diseases are neglected. Learn more about Haworthia and how to care for them to prevent problems.
