Pests & Diseases

The green vegetable bug is a shield-shaped stink bug that dimples beans and tomatoes and reeks when handled. Hand-picking and protecting its natural enemies keep it down.

Garden weevils feed at night, leaving scalloped notches on leaf edges, while their grubs chew roots out of sight. Because they cannot fly, barriers work well.

Fungus gnats are the small dark flies over damp potting mix, and it is their larvae that stall seedlings. Letting the mix dry is the single most effective fix.

Cutworms hide in the soil by day and fell young seedlings at ground level overnight. A simple collar is the single best defence.

Mealybugs look like small blobs of white cotton tucked into leaf joints and stems. They are stubborn, so here is the patient approach that clears them.

Scale insects sit still on stems and leaves like small fixed bumps, and the soft kinds drip honeydew that grows sooty mould. Here is how to clear them.

Thrips rasp at leaves and flowers, leaving silvery streaks and distorted growth, and some spread tomato spotted wilt virus. Here is how to manage them.

Slugs and snails feed at night and after rain, leaving ragged holes and silver slime trails. Here is how to protect seedlings and strawberries without anything harsh.

Armyworms are night-feeding caterpillars that march in groups and can strip sweet corn, lawns and leafy crops fast. Here is how to spot them and keep them in check.

Most garden ants are useful, but they turn into a problem when they farm aphids and scale for honeydew. Here is how to manage them, and when to report fire ants.

Whitefly rise in a cloud when you brush a plant and leave sticky honeydew behind. Here is how to control them without making the problem worse.

Spider mites speckle leaves and spin fine webbing in hot, dry weather. Here is how to spot them and why a general insecticide often makes it worse.