Pests and problems2 min read

A 5-minute pest check

Catch bugs early, while they're still easy to stop

Make it a habit

Most pests are easy to beat when you find a few and hard when you find hundreds. Look your plants over about once a week, and take a quick glance whenever you water or handle them.

Watch new plants most closely. Many pests arrive on plants just bought or received as gifts.

Where to look

Pests hide where you don't usually look, so check each of these spots.

Under the leaves, where most pests start.
Along the stems and in the joints where leaves meet them.
On new shoots, buds and flowers.
On the surface of the soil.

Tools that help

A 10x hand lens makes tiny pests easy to see. To check for spider mites, shake a leafy shoot over a sheet of white paper and watch for specks that start to move.

Yellow sticky cards catch flying pests such as fungus gnats, whiteflies and winged aphids. They won't end an infestation, but checking them each week shows you whether numbers are rising.

What the clues mean

Most pests leave a calling card.

Sticky, shiny leaves or a black, sooty film: aphids, soft scale, mealybugs or whiteflies.
Fine webbing and tiny pale speckles on the leaves: spider mites.
White, cottony tufts along veins and in leaf joints: mealybugs.
Brown or gray bumps that don't move: scale insects.
Silvery patches with tiny black specks: thrips.
Little dark flies running over the soil: fungus gnats.
Tiny white insects that fly up when you brush the leaves: whiteflies.

If you find pests

Move the plant away from your others right away. Cut off the worst leaves, then wash the pests off with a strong spray of water. A good rinse alone works well on spider mites and aphids.

If they come back, use an insecticidal soap or horticultural oil labeled for houseplants and that pest. Some plants are damaged by soap, so test a few leaves and wait 2 days first.

Follow the label exactly and repeat as it directs. Keep kids and pets away from treated plants, and wash your hands when you're done.

Sources

General guidance, not a diagnosis. Written by PlantWiz in our own words from the sources above.