Frequently Asked Questions about Fireblight
1. What is the fireblight plant disease?
Fireblight is a disease of fruit trees and ornamental plants, caused by the Erwinia amylovora bacterium. It is classified as a quarantine disease. It is the most harmful bacterial disease of certain plants in the rose family (Rosaceae), and is considered to be the most harmful fruit tree disease in Europe and the Mediterranean countries. The EU has granted Finland the status of a protected zone with respect to fireblight.
2. What is a protected zone?
If a harmful pest or disease is absent from a EU Member State or part of its territory, it can request the EU to grant it the status of a protected zone against the organism in question. A protected zone is a geographical area from which the organism is absent, despite favourable environmental conditions. According to EU legislation, Finland is a protected zone against fireblight. This protection will be withdrawn if this quarantine organism permanently spreads to the area.
3. What does such protection mean with respect to fireblight?
If fireblight is found in Finland, its spread must be prevented and occurrences eradicated. Such protection benefits plant health. It imposes certain requirements on other EU Member States which sell host plant seedlings to Finland. For example, seedlings cannot contain fireblight, the import of seedlings is only allowed from another protected zone or its buffer zone, and importing seedlings and other plant propagation material from non-EU countries is prohibited.
4. In which plants does fireblight occur?
All host plants belong to the rose family (Rosaceae). This family includes important crops such as the apple and pear. In many countries, fireblight is the most harmful disease to affect such species. Other common host plants are the juneberry, cotoneaster, hawthorn and rowan. However, not all plants in the rose family are hosts of fireblight.
5. What are the symptoms of fireblight in plants?
The symptoms of fireblight vary little between different host plants. Inflorescences wither and die, dead flowers grow dry and dark, even almost black, but do not usually fall off. Young shoots and twigs wither, turn brown, and their tips bend downwards (the so-called "shepherd's crook symptom"). Necrotic areas form in the leaves or the leaf stalk and the midrib blackens. Developing fruit turn brown or black and wither. Similarly to flowers, they do not fall off but mummify. Eventually, the disease spreads into the thicker branches and the trunk, forming necrotic areas which can surround the whole branch or trunk. At this stage, the tree will rapidly die. In warm and humid conditions, the necrotic areas, fruit and flowers emit white bacterial slime, which may later turn yellow.
6. Are these signs sufficient for diagnosing the disease?
Other bacterial and fungal diseases may cause similar symptoms. For this reason, several laboratory tests are needed to diagnose the disease.
7. Can fire blight cause symptoms in humans, for example after eating an infected apple or pear?
It cannot. Like other plant diseases, fireblight only harms plants. It is harmless to humans.
8. Where does fireblight occur?
Fireblight is originally from North America, from where it spread to Europe in the late 1950s. Since then, it has spread southwards and eastwards through Europe, currently occurring from place to place in most EU Member States. In many countries, contamination does not affect the entire territory, but there are clear areas which have been granted the status of a protected zone. Finland and Estonia are the only countries with no occurrences of fireblight so far.
9. What should I do if I suspect that fireblight has spread to my farm or garden?
If you have a professional fruit plantation or plant nursery, you must contact the plant health inspectors of your local ELY Centre, or, in the Uusimaa or Southwest Finland regions, Evira's plant health inspectors. They will make an inspection visit and collect samples, if needed. Their contact information is available here. If fireblight symptoms occur in fireblight host plants which grow in a private yard or garden, you should contact plant health inspectors as instructed above.
10. How are the authorities prepared for possible fireblight occurrences?
Evira already has a contingency plan which will be followed if fireblight is observed in Finland. This plan includes detecting the origin of plants thought to be infected. Control visits will be made according to the risk of the infection spreading and laboratory test results.