Feathered pink

Slugs and snails

What you will see

Irregular holes in soft leaves and young shoots and slime trails; they feed at night.

How to protect

1. Prevention

   • Plant sturdy potted plants, not delicate young seedlings.
   • Water in the morning, not the evening (evening watering helps them move around).
   • Encourage their natural enemies: birds, hedgehogs, toads, ground beetles.
2. By hand evening, after rainPick them off by hand on damp evenings and take them far away. Traps: hollowed-out citrus halves placed cut side down, or sunken containers of beer; check in the morning.
3. Biological when the soil is warm and moistSlug-specific nematodes (from a biological control supplier) are watered into the soil.
4. Chemical — only when nothing else helps according to the product labelLast resort only: a product authorised in your country against slugs and snails. Try non-chemical methods first.

Aphids

What you will see

Colonies of tiny insects on shoots and buds, sticky honeydew, curled leaves.

How to protect

1. Prevention

   • Check plants regularly from spring.
   • Encourage ladybirds, hoverflies, lacewings and parasitic wasps.
2. By hand as soon as it appearsRub off colonies by hand or wash them off with a jet of water.
3. Biological spring to summerRelease lacewing larvae, aphid midge larvae or ladybirds.
4. Gentle spray in a heavy infestation, repeatPotassium soap (fatty acids) or plant oil.
5. Chemical — only when nothing else helps only as a last resortA product authorised in your country against aphids.

Powdery mildews

What you will see

White powdery coating on leaves, stems and flowers; leaves may become distorted.

How to protect

1. Prevention

   • Destroy fallen infected leaves in autumn; do not over-feed, and protect from drought (stress invites powdery mildew).
2. By hand autumnPrune out infected shoots early and destroy fallen leaves.

Rusts

What you will see

Pale spots on leaves that turn into spore pustules mainly on the underside of leaves (orange, yellow, brown, black or white); in severe attacks yellowing and early leaf drop.

How to protect

1. Prevention

   • Grow in warmth, sun and free-draining soil; tarragon dislikes damp, so do not overwater.
   • Clear fallen leaves, remove diseased parts quickly, clean tools and weed.
   • Do not over-feed with nitrogen — soft new growth is quickly attacked.
2. By handFor light attacks, strip off affected leaves early; remove large amounts carefully. Do not compost summer/autumn debris (spores overwinter).
3. Chemical — only when nothing else helpsFungicides are not recommended; for edible crops, gardeners have no fungicides available with good efficacy against rust.

Fusarium wilt

What you will see

Wilting and yellowing of one side of the plant, browning of tissue in the stem.

How to protect

1. Prevention

   • Free-draining soil, change of planting site.
   • Healthy planting material.
2. By hand as soon as it is foundDig up affected plants and dispose of them away from the compost.

Root and crown rot

What you will see

Softening of the crown and roots; the plant wilts and browns despite watering.

How to protect

1. Prevention

   • Free-draining soil, no waterlogging (especially in winter).
   • Do not plant too deep.
2. By hand at the first symptomsDig up the affected plant; improve the soil with drainage; do not replant in the same place.

Thrips

What you will see

Silvery speckling of leaves and flowers.

How to protect

1. Prevention

   • Outdoors, plants usually survive even with silvery speckling; encourage natural enemies.
2. BiologicalPredatory bug Orius laevigatus and mites (mainly in the greenhouse).

Spider mites

What you will see

Leaves are speckled and bronzing, with fine webbing on the underside.

How to protect

1. Prevention

   • Reduce dust and water stress; do not use broad-spectrum insecticides, which cause mite outbreaks.
2. By handA strong jet of water on the underside of leaves.
3. Gentle sprayInsecticidal soap or oil, thoroughly on the undersides; only after mites are confirmed.

Caterpillars

What you will see

Eaten leaves.

How to protect

1. Prevention

   • Regular checks.
2. By hand once noticedPick off caterpillars by hand.

Plant viruses

What you will see

Mottled or distorted leaves.

How to protect

1. Prevention

   • Clean tools, healthy plants.
2. By hand once noticedDig up and destroy affected plants; viruses cannot be treated.