Root aphids

Aphids that feed on roots, so they're easy to miss and often mistaken for a deficiency or watering problem. You have to look at the roots.

Symptoms

• Wilting, stunting and pale or discoloured leaves that don't respond to feeding or watering changes.
• Small (2–3 mm) yellow, green or brown aphids on the roots, often with white, waxy secretions.
• Winged aphids on sticky traps near the medium, or ants in the container.

Quick checks

• Gently tip a plant out and look at the roots and root ball edges with a loupe.
• Look for white waxy fluff on roots (root mealybugs look similar).
• Check yellow sticky traps placed close to the medium.

How to fix it

1. 1
   Prevention

   Check roots before anything goes in

   Inspect the roots of new plants or cuttings before potting on, and use fresh medium.

2. 2
   Environment

   Reduce stress

   Keep the plant evenly watered and fed to the chart; RHS notes good care reduces the stress root aphids cause.

3. 3
   Physical

   Wash and repot small plants

   For young plants, wash the old medium off the roots and repot into fresh medium. Some aphids may survive, so keep checking.

4. 4
   Biological

   Root-zone predators (results vary)

   Ground-dwelling predatory mites (Stratiolaelaps / Hypoaspis) feed on a range of small, soft-bodied prey in the medium and some growers use them as part of a root-zone programme. Root aphids are hard to control, so treat this as support, not a guaranteed fix.

5. 5
   Safe treatment

   Remove badly affected plants

   If a plant is heavily infested, remove it with its medium in a sealed bag and clean the area, so the aphids don't spread to others.

Likely causes

• Root aphids brought in on plants, cuttings or used medium.
• Ants carrying aphids between containers.
• Drought stress making the damage worse.

What to avoid

• Don't keep adding feed to fix 'deficiency' symptoms without checking roots.
• Don't reuse medium from an infested plant.
• Don't let containers dry out hard, which makes root aphid damage worse.

Prevention

• Fresh medium every run.
• Quarantine and root-check new plants.
• Yellow sticky traps near the medium to spot winged adults.

Monkey products that can help

Root Shoot

Designed to build root mass and support a healthy root zone while the plant recovers.

Follow the feed chart: 2 ml per 10 L in growth weeks 1–2, then 3 ml per 10 L from growth week 3 to flower week 5.

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Stress

Monkey say silicon helps the plant manage stress; it can help the plant cope while you deal with the cause.

2 ml per 10 L every week. Always add it to the water first and mix thoroughly before adding anything else.

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Products support a healthy plant. They don't replace fixing the cause.

When to get help

If you find root aphids on several plants, or a plant keeps declining after repotting, email info@monkeynutrients.co.uk with photos of the roots, or ask a biological control supplier.

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