Woolly Aphids
Eriosomatinae
Sap-Sucking Insects Moderate Risk 1-2 mm body (fluff up to 5 mm)
📖 Description
Woolly aphids are a subfamily of aphids distinguished by their covering of white waxy filaments. Unlike regular aphids, many woolly aphid species alternate between two host plants during their lifecycle, spending part of the year on one host and migrating to another. The woolly wax covering protects them from predators and desiccation, making them harder to control with contact insecticides. Some species induce gall formation on their host plants, which can be disfiguring but rarely fatal.
⚠️ Symptoms to watch for
- Fluffy white wax deposits on stems and branches
- Gall formation on leaves and stems
- Stunted new growth on affected branches
- Honeydew and sooty mold on surfaces below
- Bark cracking on heavily infested branches
🩹 Treatment
- Prune out affected branches and destroy (organic)
- Spray with insecticidal soap (organic)
- Apply neem oil to suffocate colonies (organic)
- Use systemic dinotefuran for severe infestations (chemical)
- Apply dormant oil spray in winter (organic)
🌿 Organic treatments
- Prune out affected branches and destroy
- Spray with insecticidal soap
- Apply neem oil to suffocate colonies
- Apply dormant oil spray in winter
🧪 Chemical treatments
- Use systemic dinotefuran for severe infestations
🛡️ Prevention
- Inspect trees regularly for white wax deposits
- Prune trees to improve air circulation
- Encourage natural predators like hoverflies and lacewings
- Apply dormant oil in late winter to kill overwintering eggs
🪴 Affected plants
- Apple Trees
- Elm Trees
- Hawthorn
- Crabapple
- Beech
- Alder
🦋 Natural predators
- Ladybugs
- Lacewings
- Hoverfly Larvae
- Syrphid Flies
🌱 Host plants
- Malus domestica
- Ulmus spp.
- Crataegus spp.
- Fagus sylvatica
🔄 Lifecycle
- Most species have complex lifecycles with alternating hosts.
- They overwinter as eggs on the primary host (usually elm or apple).
- In spring, fundatrices hatch and reproduce parthenogenetically, producing winged forms that migrate to secondary hosts.
- In autumn, winged forms return to the primary host to lay eggs.
- Up to 10-12 generations per year are possible in warm climates.
📅 Season
- Spring to Fall (peak in summer)
🔎 Appearance
- Small dark aphids covered in dense white or gray woolly wax filaments, making them look like tiny tufts of cotton or wool.
- The wax covering makes them appear much larger than their actual body size.
💥 Damage level
- Moderate
🔁 Reproduction rate
- Rapid
🗺️ Geographic regions
- North America
- Europe
- Asia
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