Question 1

What causes aphid infestations on houseplants?

Accepted Answer

Aphids spread from infested plants, through open windows, or on clothing and tools. Warm temperatures and high-nitrogen fertilisation encourage rapid population growth. New plant purchases are the most common introduction route.

Question 2

How do I know if I have spider mites?

Accepted Answer

Hold a white sheet under the plant and tap the leaves. If tiny moving specks fall onto the paper, you have spider mites. Stippled silver dots on leaf surfaces and fine webbing between leaves and stems are also definitive signs.

Question 3

How do I get rid of whiteflies on houseplants?

Accepted Answer

Use yellow sticky traps to catch adults, then spray all leaf surfaces with insecticidal soap or neem oil every 3–4 days for at least 4 cycles. The nymph stages on leaf undersides are resistant to many sprays, so persistence is essential.

Question 4

How do I identify thrips on my plant?

Accepted Answer

Shake a leaf or flower over white paper — tiny yellowish or dark elongated insects will fall out. Look for silvery, shiny scarring on leaf surfaces, black frass dots on undersides, and new leaves emerging deformed or with brown streaks.

Question 5

How do I get rid of fungus gnats in houseplant soil?

Accepted Answer

Allow the substrate to dry completely between waterings — this is the most effective control. Apply Bacillus thuringiensis israelensis (Bti) as a soil drench every 7–10 days for 4–6 cycles to kill larvae, and place yellow sticky traps at soil level to catch adults.

Pest Diagnosis & Solutions