Whether you’re a beginner or a plant enthusiast, few things are more frustrating than discovering your beloved decorative plants have been attacked by pests. Small, often invisible to the naked eye, these invaders can compromise plant health and even lead to their death if not treated quickly. In this article, we’ll cover the main types of pests that affect houseplants and the most effective and sustainable ways to control and eliminate them.
1. Aphids
Description: Small, soft-bodied insects (1–3 mm), green, black, or white in color. They usually appear on the undersides of leaves or on new shoots.
Damage caused:
- Suck plant sap, weakening it.
- Cause leaf deformation and curling.
- Excrete a sticky substance (honeydew) that encourages mold growth.
Control and treatment:
- Spray with a mixture of water + neutral soap or insecticidal soap.
- Apply neem oil weekly.
- Attract natural predators (e.g., ladybugs, if using biological control).
2. Mealybugs
Description: White, cottony-looking insects that accumulate at leaf joints and on the undersides.
Damage caused:
- Suck sap, weakening the plant.
- Can cause yellowing, mold, and even leaf drop.
Control and treatment:
- Remove with a cotton swab soaked in alcohol.
- Spray with neem oil or water and coconut soap.
- Isolate the plant to prevent the spread.
3. Spider mites (Red mites)
Description: Tiny arachnids that are hard to see without a magnifying glass. Leave silky webs between leaves.
Damage caused:
- Cause yellow spots and speckling on leaves.
- Promote leaf drying and fall.
- Prefer dry, poorly ventilated environments.
Control and treatment:
- Increase ambient humidity (they hate moisture).
- Spray with water + neutral soap or neem oil.
- Introduce beneficial mites (Phytoseiulus) if using biological control.
4. Whiteflies
Description: Tiny white-winged insects that fly off when the plant is shaken.
Damage caused:
- Suck sap and reduce plant vigor.
- Excrete honeydew, encouraging mold.
- Are vectors of viral diseases.
Control and treatment:
- Use yellow sticky traps.
- Spray with neem oil or insecticidal soap.
- Introduce parasitic wasps (Encarsia formosa) in advanced cases.
5. Thrips
Description: Very small, elongated insects (black or brown) that move quickly.
Damage caused:
- Scratch plant tissue and suck sap.
- Cause silvery spots and deformed leaves.
- Transmit viruses.
Control and treatment:
- Remove heavily affected leaves.
- Apply neem oil or potassium soap.
- Use blue sticky traps to monitor/control.
6. Scale insects
Description: Hard-shelled or waxy insects attached to stems and leaves. Look like small brown “bumps”.
Damage caused:
- Suck sap silently, weakening the plant over time.
- Often go unnoticed until infestation is severe.
Control and treatment:
- Remove manually with a brush or swab soaked in alcohol.
- Use neem oil or citrus oil.
- Apply mineral oil or specific insecticides in case of resistance.
Prevention tips
The best way to control pests is to prevent them. Here are some key measures:
- Inspect new plants before bringing them home.
- Quarantine new acquisitions for 1–2 weeks.
- Keep the foliage clean and well-ventilated.
- Avoid overwatering or nutrient imbalances (which attract pests).
- Disinfect tools before use (scissors, tweezers, etc.).
- Use natural repellents preventively (neem oil, garlic tea, horsetail infusion).
Natural recipes for homemade insecticides
- Garlic and chili tea:
- Blend 1 clove of garlic + 1 chili pepper in 1 liter of water.
- Let sit for 24h, strain, and spray on the plant.
- Cinnamon water:
- Helps prevent fungal and pest proliferation.
- Mix 1 tsp of powdered cinnamon in 500 ml of water.
- Neem oil solution:
- Mix 1 tsp neem oil + 1 drop of neutral soap in 1 liter of water.
- Shake and spray every 5–7 days.
When to use chemical pesticides?
Use chemical pesticides only as a last resort and with care:
- Always read the label and follow safety recommendations.
- Avoid using indoors without proper ventilation.
- Prefer targeted, low-impact insecticides.
Recovery after the attack
After eliminating the pests:
- Prune damaged leaves.
- Gently clean the leaves.
- Apply a light fertilizer to help the plant regain strength.
- Keep the plant in a bright and well-ventilated spot, but avoid direct sun immediately after treatment.
Pest infestations are common and can be controlled with observation, timely action, and appropriate methods. Whether through natural treatments or, if necessary, chemical interventions, it is possible to restore health to your ornamental plants and maintain a balanced indoor environment. The key is to act as soon as the first signs appear and make plant care a regular part of your routine.