Fire blight: how to recognise and treat it

Disease

Fire blight — Photo: Sebastian Stabinger, CC BY-SA 3.0, Wikimedia Commons

Symptoms

Blossoms wilt and turn brown to black at flowering time.
Young shoots wilt and bend over at the tip like a shepherd's crook.
Dead blackened leaves and fruit stay on the branches, so the tree looks scorched.
In wet weather a light tan or white bacterial ooze seeps from infected bark and cankers.

Organic treatment

Cut out infected shoots promptly, 30 cm into healthy wood on small branches and 60 cm on larger ones.
Disinfect pruning tools between cuts and burn or bin the prunings.
Pick off late secondary blossoms before they open.

Chemical treatment

Copper spray every 4–5 days during bloom once average temperatures pass 16 °C; it only limits spread, and follow the label dose and pre-harvest interval.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Prevention

Avoid heavy nitrogen feeding, because fast-growing shoots are hit worst.
Do major pruning in winter, when the bacteria are not spreading.
Pear and quince are the most susceptible hosts; watch them closely at bloom.

Plants it affects

Sources

Figures checked against these sources.