Aphids (Greenfly, Blackfly) and Whitefly: How to Get Rid of Them

Greenfly and blackfly are aphids: small, soft-bodied insects that cluster on new growth and suck the sap. Indoors and under glass they can breed all year, and chillies, peppers and tomatoes are common targets, often alongside whitefly. This guide covers how to spot aphids and whitefly, how to get rid of them with the pest control products we sell, and how to keep them out.

What aphids look like

Colour: green (greenfly), black (blackfly), grey, pink or yellow.
The shape: small, pear-shaped and slow, with two short tubes pointing back from the rear. Most are wingless; winged ones appear when a colony gets crowded.
Where they sit: packed together on growing tips, under young leaves and on flower stalks.
Root aphids feed underground: the plant wilts or yellows for no clear reason, and small pale insects show on the root ball.

Woolly aphid, the white fluff on apple trees, is a garden pest we do not cover here.

Signs of aphids on plants

Curled, puckered or twisted new leaves and stunted tips (our yellow leaves guide covers other causes).
Sticky leaves, pots and shelves: honeydew, the sugary waste aphids pass. Black sooty mould grows on it, and outdoors ants tend aphids for it.
White flecks on the leaves: skins shed as aphids grow.

For most of the year colonies are all female and give birth to live young without mating, so a few soon become hundreds. Aphids can also spread plant viruses, so act early.

Greenfly and blackfly on chilli and tomato plants

Chillies kept indoors over winter are often hit, with no natural predators indoors to keep numbers down. Check the tips, newest leaves and flower stalks each time you water. These are crops you eat, so read the label for whether a product can go on edible plants and how close to harvest you can spray: the SB Plant Invigorator page says it is safe for use on edible crops, and the Athena IPM page allows it from seedling to week 5 of flowering or fruiting. After week 5, wash aphids off by hand or use a product whose label allows it.

How to get rid of aphids

Start by hand. Squash small colonies or wash them off with a jet of water. Cut off badly infested tips with clean scissors and move the plant away from the rest.
Hang sticky traps. Sticky Fly Traps catch winged adults and help you spot an infestation early, but their page says they will not normally solve a problem alone.
Spray thoroughly. SB Plant Invigorator's page says it kills spider mite, aphid and whitefly. Athena IPM's page says it kills many soft-bodied insects; wear protective gear and spray with the fans off, and the lights off or in early morning sun. Wet the tips and every leaf underside: the Athena page recommends a pump sprayer, and the Garden HighPro Pumpro Sprayer 2L has a rotatable head for awkward spots.
Or dust. Desi Dust is diatomaceous earth; its page names aphids and whiteflies and says it damages their outer shell so they dry out. Dust the affected parts by hand or with an applicator.
Repeat. No spray reaches every aphid, and new ones are born or fly in. Treat again as the label says (Athena IPM: at least three sprays, three days apart, for most pests) until you stop finding aphids.
Root aphids: treat the medium. CX Tanlin, in our sciarid fly killer section, is a biological control whose page names root aphids, fungus gnats and thrips. It goes on the growing medium or into the watering, at the rate on the label.
Clean up. Wipe off honeydew and sooty mould with a damp cloth, and clean the room and kit between crops (see cleaning products).

Ladybirds and lacewing larvae eat aphids, and parasitic wasps lay their eggs in them; specialist suppliers sell these for greenhouses. Many sprays harm them, so check the label first.

Sprays, dusts and traps we sell

Pest products we sell, as their product pages describe them: makers' claims, not a promise.
Product	Pests its page names	How it is used	Dose
SB Plant Invigorator	Spider mite, aphid, whitefly	Spray; weekly from early in the plant's life	At the rate on the label
Athena IPM	Many soft-bodied insects	Foliar spray, lights and fans off	Treatment 24-32 ml per litre; prevention 16-24 ml per litre
Desi Dust	Spider mites, thrips, aphids, whiteflies	Dust by hand or applicator	At the rate on the label
Sticky Fly Traps	Greenfly, whitefly, aphids, blackfly, fungus gnats, midges	Hang near the plants; 5 traps and 3 hooks a pack	–
CX Tanlin	Root aphids, fungus gnats, thrips	Into the medium or the watering	At the rate on the label

Which to pick: SB Plant Invigorator or Desi Dust on the leaves, as both pages name aphids and whitefly; CX Tanlin for root aphids.

Whitefly: the same approach

Whitefly are tiny white, moth-like insects that sit under the leaves and rise in a cloud when you brush the plant; under glass they are a familiar pest of tomatoes, cucumbers and peppers. Their young are flat, pale scales fixed under the leaf, and like aphids they leave honeydew and sooty mould. Treat them the same way, with two differences:

Lean on the traps. Adult whitefly are drawn to yellow, and Sticky Fly Traps are yellow and sticky on both sides: hang them just above the plants.
Keep at the undersides. The scales do not move, and new adults keep emerging from them, so spray under the leaves and repeat as the label says.

Keeping aphids and whitefly out

Check new plants. Look at the tips and leaf undersides of new plants and cuttings before they come in, and keep them apart for a week or two if you can.
Screen the intake. Winged aphids and whitefly can be drawn in on the air. RAM Bug Barriers are fine mesh screens that fix to the side of an intake fan with Velcro, for fans from 100 to 315 mm; their page says to check them regularly for debris.
Coat the leaves. Canna say CannaCure forms a second natural skin that pests stick to and starve on. The Biobizz Leaf Coat page says this natural latex spray helps raise resistance to pests and moulds and degrades roughly two weeks after spraying; we tested it and call it a protective layer, not a cure.

Quick answers

How do I get rid of aphids on plants?

Wash or squash what you can, then spray or dust the tips and leaf undersides and repeat as the label says. Root aphids are treated in the growing medium.

Are black aphids the same as greenfly?

Both are aphids: blackfly is the usual name for black ones, greenfly for green. Different kinds, same treatment.

How do I get rid of whitefly?

Hang yellow sticky traps just above the plants for the adults, spray or dust the leaf undersides where the young sit, and repeat as the label says until the traps stop catching new adults.

Where do aphids come from indoors?

Winged aphids fly in through doors, windows and fan intakes, especially in the warmer months; others arrive on new plants and cuttings. Indoors, warmth lets them breed all year.

More Growers' Guides

Not sure what you need? Call the shop on 0117 971 3000 or pop in to the Bristol store and we'll help you pick.