Fireblight
Erwinia amylovora
Role in the garden
A bacterial disease of pome fruit (apple, pear, quince) and of several ornamental and hedging shrubs (hawthorn, cotoneaster, pyracantha, rowan): flowers and shoots turn brown and dry out as if scorched, the tips of the shoots bend into a shepherd's crook. In the European Union it has been a regulated non-quarantine pest (RNQP) since 2020: no more compulsory reporting or control for gardeners, but rules remain for the movement of plants, and it is still a quarantine pest in a few protected zones (in France, Corsica).
Activity period
Infections at flowering (April-June) and on soft shoots in hot, stormy summers
How to attract / manage it
Severe, immediate pruning of affected parts with tool disinfection; in case of doubt, the FREDON or the regional plant-protection service (DRAAF-SRAL) can advise.
Practical guide
Where to find them
Apple, pear, quince, hawthorn, cotoneaster, pyracantha, rowan, medlar, photinia. The bacterium enters through the flowers and wounds, carried by rain, insects and tools.
Prevention
Avoid cotoneaster, pyracantha and hawthorn hedges near fruit trees in affected areas; prefer less susceptible varieties; do not force growth with nitrogen; disinfect secateurs between two trees (alcohol or diluted bleach); watch at flowering.
Early signs
Flowers that turn brown and stay attached, young shoots blackening from the tip and bending into a crook, brown withered leaves that remain on the tree, droplets of whitish to amber ooze in damp weather, cankers on the bark.
Action / control
Cut 30 to 50 cm below the visibly affected zone, in dry weather, disinfecting the tool between each cut, and burn or dispose of the waste (never in the compost). Grub out badly affected trees. No curative treatment available; copper has only a limited preventive effect. Since 2020 fireblight is no longer notifiable, but the FREDON or the DRAAF-SRAL of your region can confirm a diagnosis.
Sources
- DRAAF Pays-de-la-Loire : Erwinia amylovora, feu bactérien (statut ORNQ depuis 2020)
- EPPO : datasheet Erwinia amylovora (2020)
- INRAE, Ephytia : Pomme, Erwinia amylovora (feu bactérien)
Favourite plants / resources
Related plant entries
Apple tree
A pivotal tree in the permaculture orchard, the apple occupies the upper storey and forms the backbone of a whole guild layered beneath it (Hemenway, Gaia's Garden). Its blossom benefits from being surrounded by nectar-rich companions (borage, phacelia) that feed bees and bumblebees. At its feet, comfrey provides a potassium-rich mulch biomass, white clover fixes nitrogen as a living ground cover, while garlic and tansy play the traditional role of repellent aromatics. So encircled, it structures a small ecosystem that tends towards self-reliance: covered soil, pollinators on hand and organic matter renewed on the spot.
Pear tree
A high layer (4-6 m on quince, 8-12 m on seedling rootstock). CROSS-pollination obligatory: plant 2 compatible varieties. Lives 50-80 years. Tansy at its foot reputed to keep away certain pests (popular reputation, moderate effect). Comfrey in the low layer = potassium-rich mulch. Keep away from junipers (Juniperus, especially J. sabina): obligate alternate host of pear trellis rust, Gymnosporangium sabinae (RHS; PNW Pest Management Handbooks).
Hawthorn
A slow-growing but very long-lived thorny shrub, hawthorn forms the classic backbone of multifunctional country hedges: defensive thanks to its thorns, nectar-bearing at the May flowering, food-bearing in autumn (haws appreciated by birds), and a refuge for small wildlife all year round.
Quince tree
A small, hardy, unpretentious tree, with a beautiful pink spring flowering (nectar-bearing) and a very fragrant golden fruit, turned into jelly, paste (cotignac), or compote, never eaten raw. Self-fertile and modest in size, it finds its place in small orchards; it also serves as a classic dwarfing rootstock for the pear.