At a glance
- Fire blight is the most dangerous disease of pome fruit. It is caused by bacteria, spreads at breakneck speed and can kill whole trees.
- It is notifiable. If you suspect it, you inform the responsible plant-protection authority and do not prune on your own initiative.
- You recognise it by suddenly wilting, brown-black shoots that look as if burnt and curl at the tip like a shepherd's crook.
- Affected are apple, pear, quince and many ornamental shrubs like hawthorn and cotoneaster. A sure sign is milky ooze droplets.
When a shoot on apple or pear wilts overnight, turns black and looks as if a flame had scorched it, caution is due. That is possibly fire blight, the most feared disease of pome fruit. Unlike with a fungus, here fast, correct action counts for more than any home remedy.
This article is the detail edition to the overview in Recognising fruit tree diseases. It shows you how to recognise fire blight and what to do on suspicion, because here special rules apply.
How to recognise fire blight
The damage picture is dramatic and usually clear. Blossoms, leaves and young shoots wilt suddenly, turn brown to black and look as if burnt. Typically the wilted leaves stay hanging on the twig instead of dropping. The shoot tips curl characteristically downward, like a shepherd's crook.
Another sure sign appears in warm, humid weather: at affected spots, milky-white to amber ooze droplets well out, the bacterial slime. The pathogen, the bacterium Erwinia amylovora, spreads at breakneck speed via rain, insects and above all pruning tools.
Fire blight is notifiable
In Germany, fire blight is a notifiable plant disease. If you suspect it, you must inform the responsible plant-protection authority. On no account prune wildly at the plant yourself, because on the secateurs you only spread the bacteria further. Wait for the instruction of the experts; they know the right steps for your region.
What you must do, and what not
Do not prune yourself
The first and most important step is to stay calm and not prune in a panic. Every improper cut spreads the bacteria in the tree and into the neighbouring garden.
Report the suspicion
Report the suspicion to the plant-protection authority. Experts confirm the diagnosis and set how to proceed, from cutting back to, in the worst case, felling the tree.
Mind tools and hygiene
If cutting is done after all, it goes far into the healthy wood, and the tools are thoroughly disinfected after each cut. The affected material is disposed of by the rules, usually burnt.
Prevent through restraint
Do not feed too heavily, because soft, lush foliage is especially susceptible. Near orchards, do without highly susceptible ornamental shrubs like hawthorn or cotoneaster.
Host plants and confusions
Fire blight attacks only rose-family plants related to pome fruit: apple, pear, quince, medlar and ornamental shrubs like hawthorn, cotoneaster, firethorn and rowan. It can be confused with brown rot shoot blight or with frost damage, but these are not contagious and not notifiable. When in doubt: better to report once too often than to overlook fire blight.
Do not cut, report. With fire blight, fast, correct action by the rules decides, not your own busywork.
The core rule for fire blight
Frequently asked questions
How do I reliably recognise fire blight?
By suddenly wilting, brown-black shoots that look burnt and curl at the tip like a shepherd's crook. The wilted leaves stay hanging. In warm, humid weather milky ooze droplets emerge. This combination is typical.
Why is fire blight notifiable?
Because it is highly contagious and can destroy whole orchards and wild stands. So it does not spread, the authorities must know of every suspicion and act in a coordinated way. That is why reporting is mandatory.
Can I save the tree myself?
Only in consultation with the experts. A light early attack can sometimes be stopped by generous cutting back into healthy wood, with strict tool hygiene. With heavy attack, often only felling remains, to protect the surroundings.
Which trees and shrubs are affected?
Only pome fruit and related ornamental shrubs: apple, pear, quince, medlar, plus hawthorn, cotoneaster, firethorn and rowan. Stone and soft fruit and vegetables are not affected.
How can I prevent it?
With moderate feeding, because soft foliage is more susceptible, and by keeping highly susceptible ornamental shrubs away from fruit trees. Fire blight cannot be prevented entirely, but you can lower the risk and spot it early.
Legal note
Fire blight is a notifiable plant disease. If you suspect it, be sure to inform the responsible plant-protection authority and follow its instructions. This article is for information and is no substitute for official advice.
Sources
- Julius Kühn Institute: fire blight, recognition and reporting duty
- Bavarian State Institute for Viticulture and Horticulture (LWG): fire blight in the home and allotment garden
- Related in the magazine: Recognising fruit tree diseases and Pear rust
Spotted a mistake?
