Cacti and succulents They are famous for their resilience, their ability to survive in arid environments, and their ease of care. However, this reputation often leads to underestimating the problems they can be exposed to, especially regarding pests, diseases and physical disorders that can cause irreversible damage if they are not detected and treated in time.
This article collects in a detailed and exhaustive way The main pests and diseases that can affect cacti, succulents and other succulent plants. Included Prevention tips, symptoms, effective treatments, and underlying causes, as well as biological details about harmful agents, to help you keep your plants healthy and vigorous both indoors and outdoors.
Most common pests and diseases in cacti and succulent plants
Cactus, succulents and succulents They are botanical concepts with differences, but they share many vulnerabilities and care needs. Although they excel at withstanding inclement weather, drought, intense sun, and relative neglect, they can be attacked by multiple types of pests and diseases.
Threats do not have a fixed time: they can appear at any time and, if a plant shows signs of weakness, it is essential to act quickly, since many pests They multiply rapidly and can infect other plants. from your collection.
Prevention, regular inspection, and awareness of the initial symptoms are the best protection against serious damage or the loss of your animals.
Main pests in cacti and succulents
The pests They are one of the most common problems. They affect both potted and outdoor plants and can attack leaves, stems, roots, buds, and even flowers. They are described below. the most common pests, its symptoms and how to combat them.
Mealybugs
The mealybug It is possibly the most feared and recurring pest in cacti and succulents. There are several types:
- Cottony mealybug: Pseudococcus spp. They produce a white cottony mass on leaves, stems, and roots. They thrive in warm, dry environments, although they can also appear due to excess humidity and lack of ventilation. The main symptom is the cottony mass, although it's harder to detect on roots.
- Shell scale or limpet: They stick their shield-like bodies to the plant tissue, forming 1-2 mm brown or whitish scabs. They are easy to see.
- Root mealybug: Rhizoecus spp. It develops underground, and you'll only notice that the plant isn't growing or shows weakness. When you remove the pot, you'll see white buildup on the root ball.
- Eriococcus coccineus: a small, brownish species that can be confused with a natural stain or scab on the plant.
Symptoms: Leaves and stems covered with cottony fabric, growth stagnation, general weakness, spots or crusts, and sticky discharge. In severe attacks, they can cause death within days.
Prevention and control: Frequent inspection is essential. Remove them manually with a paintbrush or cotton ball soaked in alcohol, use systemic insecticides (such as Folithion, Baytroid, or specific products for mealybugs), and, in the case of root mealybugs, soak the pot in water with insecticide for 20-30 minutes. Apply preventative treatments in early spring and fall.
Caterpillars
The caterpillars and larvae of moths or butterflies They can cause significant damage, especially at night, when they feed most. They eat leaves, tender shoots, and sometimes flowers.
Symptoms: holes, bites in leaves and soft tissues, deterioration of shoots and sudden loss of vigor.
Prevention and control: Inspect at night and remove caterpillars by hand, supplementing with multipurpose insecticides if the infestation is widespread. Insecticides for mealybugs are usually effective. Avoid excess organic matter that attracts moths.
Soil worms
Some worms and grubs (such as the white grub) feed on the roots of succulents and cacti, causing stunted growth and progressive weakening. They are difficult to detect because they operate hidden beneath the substrate.
Symptoms: very slow growth, wilting, easy detachment of the plant from the pot, eaten roots or with visible lumps.
Prevention and control: Use clean potting mixes in new pots and disinfect garden soil. If you detect the presence, remove the plant, remove damaged parts, and repot in fresh potting mix, applying soil insecticides when necessary.
Snails and slugs
They take advantage of the moisture after rain or irrigation, usually emerging at night and devouring young shoots and more succulent areas. They can destroy small plants in a single attack.
Prevention and control: Use physical barriers, beer traps, or specific products based on metaldehyde or methiocarb. Check and replenish after rain. Collecting them manually at dusk is also effective.
Mites
Mites, especially the Red spider (Tetranychus urticae), are pests that are difficult to detect with the naked eye. They multiply in warm, dry environments. If you have a magnifying glass, you'll see tiny spiders running among the thorns and on the undersides of leaves.
Symptoms: Yellow, gray, or brown spots on leaves, a dull or grayish appearance, fine webbing between thorns, and malformations. If left untreated, these can cause leaves to drop.
Prevention and control: Improve ventilation and maintain a certain level of humidity (without over-wetting the plant). Use specific acaricides and check frequently. Natural predators (ladybugs) are useful for biological control.
Aphids
Aphids (green, black, yellow) form colonies on tender shoots, flowers, and the undersides of leaves. They suck sap and excrete honeydew, which promotes fungi such as sooty mold and attracts ants.
Symptoms: curled or twisted leaves, deformed shoots, spots and necrosis, presence of ants, groups of insects visible to the naked eye.
Prevention and control: Manually remove and apply insecticides for aphids. Also combat any presence of ants, as they protect them.
White fly
This insect flies around leaves and deposits larvae on the underside. It's not as common on cacti, but it can cause damage to soft-leaved succulents.
Symptoms: yellowing leaves, premature fall, general weakening.
Prevention and control: Use yellow chromatic traps and spray with specific insecticides if the attack is intense.
Trips
The trips They are very small, yellowish, winged insects. They are found on the underside of leaves, biting and causing lesions on leaves and flowers.
Symptoms: pale, silvery or discolored spots, deformed or damaged flowers.
Prevention and control: Treatment with foliar or organic insecticides is usually sufficient in most cases.
Nematodes
They are microscopic worms that primarily affect roots, forming lumps and galls that prevent the proper absorption of water and nutrients.
Symptoms: lumps on roots, weakness, very slow growth, yellowing, leaf drop.
Prevention and control: Remove and discard the affected roots, transplant into fresh, disinfected substrate.
Grasshoppers, rodents and birds
Grasshoppers and birds occasionally attack tender leaves, especially outdoors. Rodents can chew and uproot entire plants. Sedum It is especially popular with mice and other herbivorous animals.
Symptoms and diagnosis of pest attacks
- Color changes: yellowing (chlorosis), grey spots, whitening.
- Structural damages: necrosis, dead areas, cankers, scabs or scutes.
- Malformations: leaf curling, tumors, galls, deformation of shoots and flowers.
- Production of substances: exudation of resins or gums, sticky molasses.
- Loss of vigor: : stopped growth, general weakening, falling of leaves or thorns.
Careful observation is the best tool for identifying the problem and applying appropriate treatment before it becomes worse.
Main diseases of succulent plants and cacti
The diseases in cacti and succulents They are usually caused by fungi, bacteria and, to a lesser extent, viruses. Although these plants are resistant, cultivation errors (excess humidity, compact soil, lack of light) are the main entry point for pathogens.
Fungal diseases
- Fusarium wilt (Fusarium oxysporum): affects the roots, causing rot, discoloration, and wilting. It is difficult to detect early, as symptoms appear when the damage is significant. Fungal diseases in cacti and succulents
- Neck rot (Phytophthora): appears at the base of the stem, with symptoms of softening, unpleasant odor, and darkening. It spreads rapidly from bottom to top.
- Internal rot: fungi such as Pythium o rhizoctonia They cause the plant to rot inside, losing color and turning brown or black.
- Botrytis (Botrytis cinerea): a fuzzy, gray patch on the surface of leaves and stems. It thrives due to excess humidity.
- Rust (uromyces): causes small orange or brown bumps on leaves and stems. It is often accompanied by spine loss in cacti and general weakness.
bacteriosis
Caused by bacteria of the genus erwinia and others soften the internal tissues and, if it progresses, eventually destroy the plant entirely. It may begin as a dark, watery spot that spreads.
Viral diseases
Viral infections are rare but possible. It is noteworthy that mosaic virus, which produces irregular patterns, abnormal coloration, and deformed leaves and shoots. There is no treatment, and the affected plant must be removed to prevent its spread.
Factors that promote the appearance of pests and diseases
- Excessive watering: It is the number one cause of death for cacti and succulents. It encourages the growth of fungi, bacteria, and some insects. A dried-out cactus can recover, but a rotten one is rarely saved.
- Unsuitable soil: Poorly drained or compacted substrate generates water retention, lack of oxygenation and root stress.
- Lack of light: favors the weakening of the plant, making it more sensitive to pathogen attacks.
- Excess fertilization: causes abnormal growth and weakens the plant's immune system. Regular fertilization is not necessary: ​​once or twice a year is usually sufficient.
- StuffinessStagnant air encourages the development of pests such as mealybugs and fungi such as gray mold.
- Transplants at non-recommended times: Especially in winter, they weaken natural defenses and facilitate the attack of pests.
Methods for eliminating pests and diseases in cacti and succulents
The approach to a pest or disease depends on its severity and the causative agent. Generally, the combination of Preventive treatments, specific ecological and phytosanitary remedies It is the most effective form of control.
Pest treatments
- manual removal: Use a brush, cotton swab, or tweezers to remove visible insects before applying chemicals.
- Spray with soap and water: A mixture of water, potassium soap and a few drops of alcohol helps eliminate many pests in an environmentally friendly way.
- Systemic insecticides: products based on azadirachtin, diazinon or pyrethrins, especially in intense infestations.
- Spraying with diatomaceous earth: A natural product that acts as an insecticide by dehydrating insects and mites. It can be used as a powder (sprinkled) or diluted in water to spray affected areas.
- Biological remedies: Introduce natural predators, such as ladybugs or lacewings, which feed on aphids or mealybugs.
- Seasonal preventive treatments: Carry out preventive spraying in spring and autumn with systemic products to strengthen the plant's resistance.
Treatments for diseases
- Specific fungicides: Use products appropriate to the type of fungus (copper, sulfur, systemic products) and repeat the treatment every 10-15 days.
- Isolation of the affected plant: Minimizes the risk of contagion by separating the sick specimen from the rest.
- Removal of affected parts: Cuts and removes soft, rotten, or severely damaged tissue. Sterilize tools before and afterward.
- Plant waste: If the damage is irreversible, remove the affected plant before the disease spreads.
How to prevent pests and diseases in cacti and succulents
The key to a healthy crop is the preventionHere are the top tips for minimizing the risk of pests and diseases in your plants:
- Buy healthy plants and check them before introducing them. in your collection. Discard specimens with spots, scabs, thrush, or obvious weakness.
- Inspect your plants periodically, especially after rain, abundant irrigation or during seasonal changes.
- Water only when the substrate is completely dry.Excess water is the biggest enemy. Never leave water standing in the dish.
- Use draining substrates, mixed with sand or perlite to prevent moisture build-up.
- Change the soil from time to time, especially if you suspect root disease.
- Avoid wetting leaves and stems during watering, since fungi take advantage of surface moisture.
- Provides sufficient lightExpose plants to as much light as possible, monitoring the needs of each species in winter.
- Ventilate the growing area well, especially indoors, to prevent air stagnation.
- Avoid excessive fertilization and only transplant when the plant is actively growing.
- Isolate any new specimens for a few days before putting it with the rest, to check that it is free of hidden pests.
By following these recommendations, your cacti and succulents will maintain their vigor and beauty for a long time. close observation and quick action against any symptom, they are the best weapons to have healthy and spectacular plants.
If you have specific questions about the health of your cacti or notice any symptoms that are difficult to identify, don't hesitate to leave a comment. We'll help diagnose the problem and find the best solution to protect your plants.
