Pest Lexicon – Green Guardia

Aphids: Identifying & Naturally Regulating Infestations

Aphids are among the most common plant pests in gardens, on balcony plants, and houseplants. They suck plant sap, weaken growth, and can transmit diseases. With the right beneficial insects, an infestation can be sustainably regulated.

ⓘAphidoidea · Aphids #Honeydew · Ants · Leaf curling

What are aphids?

Aphids are small, usually green, black, or yellowish insects that settle in colonies on young shoots, the undersides of leaves, and buds. They multiply very rapidly – often without fertilization – and can severely weaken plants within a short period of time.

Sucking pest Rapid reproduction Honeydew

Typical signs of an aphid infestation

Curled, deformed, or sticky leaves
Visible aphid colonies at shoot tips
Honeydew on leaves or surfaces underneath
Ants on the plant (they “tend” to aphids)
Weakened growth

Green Guardia Tip: Ants are a clear warning sign. Where there are many ants, aphids are usually not far away.

Which plants are commonly affected?

Vegetable plants (e.g., peppers, tomatoes, beans)
Fruit trees & berry bushes
Ornamental plants & roses
Balcony and houseplants

Why do aphids occur?

Soft, nitrogen-rich shoots
Warm, dry weather
Few natural predators
Ants promote aphid colonies

Suitable beneficial insects against aphids

Ladybugs & Ladybug larvae

Eat large quantities of aphids
Especially effective in the larval stage
Ideal for gardens and balconies

Lacewing larvae

Also known as “aphid lions”
Very voracious and versatile
Effective even with heavier infestations

Parasitic wasps (Aphidius species)

Specifically parasitize aphids
Ideal for greenhouses & houseplants
Work sustainably at the source

Why beneficial insects are the best choice: Aphids sit openly on the plant and are easily accessible to their natural enemies. Beneficial insects regulate the infestation without harming plants or the environment.

Additional natural measures

Rinse plants with water (for light infestations)
Keep ants away (glue traps, barriers)
Fertilize according to location (avoid excessive nitrogen)

FAQ about aphids

Are aphids dangerous to plants?

Yes, a heavy infestation significantly weakens plants and can transmit diseases.

How fast do aphids reproduce?

Very quickly – under favorable conditions, new generations are produced within a few days.

When are beneficial insects useful?

As early as possible in the infestation, before large colonies form.

Why do aphids keep coming back?

Often due to ant protection or an imbalance in the natural population of beneficial insects.