Common Pests on Indoor Cacti

Cacti are generally resilient, but certain pests can still cause problems indoors. The most common pests found on cacti are:

• Mealybugs (Pseudococcidae): Small, white, cotton-like insects that cluster in crevices or on roots.
• Spider mites (Tetranychidae): Tiny, reddish or yellowish mites that create fine webs, often on new growth or between ribs.
• Scale insects (Coccoidea): Hard, brown or gray bumps attached to stems or pads.
• Fungus gnats (Sciaridae): Small black flies, usually a sign of persistently wet soil rather than a direct threat to the cactus itself.

Symptoms of Pest Infestation

• White, fluffy spots (mealybugs) on the surface or in stem joints.
• Fine, silky webs (spider mites), especially in dry conditions.
• Sticky residue (honeydew) or sooty mold on or near the plant.
• Yellowing, stippling, or deformed growth.
• Brown, hard bumps (scale insects) that do not rub off easily.

Check your cactus regularly, especially after bringing new plants home or during warm, dry periods.

Preventive Measures

• Inspect new plants for pests before introducing them to your collection.
• Keep cacti in well-ventilated areas with adequate light.
• Avoid overwatering, as persistently wet soil can attract fungus gnats and weaken the plant.
• Remove visible pests with a cotton swab or soft brush where possible.
• Quarantine affected plants to prevent spread.

When to Seek Professional Help

If pests persist after manual removal or if the infestation is severe, consider consulting a plant specialist. Some pest problems may require targeted treatment, but always check the suitability for cacti before use.

Pests vs. Other Problems

Not all spots or discolorations are caused by pests. Overwatering, sunburn, or nutrient deficiencies can also cause visible changes. If you do not see clear signs of insects or webs, check the cactus problems page for other possible causes.