Garden Pest Guide: Identify and Control Common Pests

What it looks like: Tiny pear-shaped insects, green, black or yellow, packed together on new shoots and flower buds.

Damage: Curled, distorted new growth, sticky honeydew, sooty black mould and ants walking up the stem.

Often found on: Chili, eggplant, okra, rose, hibiscus, citrus.

What to do: Spray them off with a strong jet of water or wipe them away. Repeat every few days. Use insecticidal soap or neem oil for heavy infestations, following the label, and control ants that protect them.

Prevention: Avoid too much nitrogen fertiliser, which makes soft growth they love. Check new shoots every week.

What it looks like: Tiny white winged insects on the underside of leaves that flutter up in a cloud when you touch the plant.

Damage: Yellowing leaves, weak growth, sticky honeydew and sooty mould.

Often found on: Tomato, chili, eggplant, cucumber, hibiscus.

What to do: Hang yellow sticky traps, rinse the undersides of leaves and remove badly infested leaves. Insecticidal soap can help, following the label.

Prevention: Check new plants before bringing them near others, and avoid crowding.

What it looks like: Almost invisible specks, often red or yellow. Look for fine webbing under the leaves.

Damage: Fine pale speckles on leaves that turn dull, bronzed or dry. Worse in hot, dry weather and in dry indoor air.

Often found on: Beans, tomato, chili, rose, many houseplants.

What to do: Rinse the undersides of leaves with water every few days, raise humidity, and use insecticidal soap or horticultural oil if needed, following the label. Isolate affected houseplants.

Prevention: Keep plants well watered and dust-free, and avoid very dry, hot spots.

What it looks like: Very slim, tiny insects that run or jump when disturbed, often hiding inside flowers.

Damage: Silvery streaks, black specks on leaves and distorted flowers or fruit.

Often found on: Chili, rose, orchid, onion, beans.

What to do: Use blue or yellow sticky traps, remove badly affected flowers and leaves, and spray insecticidal soap, following the label.

Prevention: Remove weeds nearby and check flowers regularly.

What it looks like: Small white, cottony clumps in leaf joints, on stems and under leaves.

Damage: Stunted growth, yellowing leaves, sticky honeydew and sooty mould.

Often found on: Citrus, hibiscus, orchid, succulents, many houseplants.

What to do: Dab each bug with a cotton bud dipped in rubbing alcohol, or wipe them off. Repeat weekly. Keep the plant away from others until it is clear.

Prevention: Inspect new plants and look in leaf joints and under pots.

What it looks like: Small brown, tan or white bumps stuck to stems and leaves that do not move.

Damage: Yellowing, weak growth, sticky honeydew and sooty mould.

Often found on: Citrus, mango, orchid, ferns, bonsai.

What to do: Scrape them off gently, dab with alcohol on a cotton bud and prune badly infested stems. Horticultural oil can be used on woody plants, following the label.

Prevention: Check stems on new plants and prune crowded branches for airflow.

What it looks like: Green, brown or striped larvae, often well camouflaged on leaves. Look for dark droppings.

Damage: Ragged holes in leaves, sometimes whole leaves eaten overnight.

Often found on: Cabbage and mustard greens, okra, tomato, chili, lettuce.

What to do: Pick them off by hand in the evening or early morning. A biological spray called Bt works on leaf-eating caterpillars, following the label.

Prevention: Cover leafy crops with fine insect netting and check leaf undersides for eggs.

What it looks like: Soft-bodied slugs or shelled snails that come out at night and after rain, leaving shiny slime trails.

Damage: Irregular holes in leaves, and whole seedlings eaten.

Often found on: Lettuce, mustard greens, seedlings, strawberry.

What to do: Go out at dusk and collect them. Use barriers such as copper tape around pots and shallow traps. Remove hiding places.

Prevention: Water in the morning so the soil is drier at night, and clear fallen leaves and boards.

What it looks like: Small flies that sting ripening fruit to lay eggs. Maggots live inside the fruit.

Damage: Small puncture marks, soft or rotting patches, and fruit that drops early with maggots inside.

Often found on: Cucumber, bitter gourd, melon, mango, guava, chili, citrus.

What to do: Pick up and destroy fallen and infested fruit (seal it in a bag, do not compost it). Cover young fruit with paper or net bags. Use traps with lures sold locally for fruit flies, following the label.

Prevention: Bag fruit early, harvest on time, and keep the ground clean under fruiting plants.

What it looks like: Small dark flies that hover around potted plants and the soil surface. Larvae are tiny and live in wet soil.

Damage: Mostly a nuisance. Many larvae can damage seedlings and the roots of young plants.

Often found on: Houseplants and seedlings in constantly wet potting mix.

What to do: Let the top few centimetres of soil dry between waterings, use yellow sticky traps for the adults and remove the top layer of soil if it stays wet.

Prevention: Do not overwater, and use a well-draining mix.