Apple tree has black shoots: it may be fire blight
Created: 06/18/2022, 09:00
By: Ines Alms
Brown-black wilted shoot tips, leaves or fruit on the apple tree can indicate fire blight, a disease caused by a bacterium.
Freising - This fire is difficult to extinguish: Fire blight is a woody disease caused by the bacterium "Erwinia amylovora", which can attack apple and pear trees as well as ornamental quinces and native wild fruit hedges.
If you act quickly and consistently, you can prevent the spread of the disease.
Apple tree has black shoots: it may be fire blight
Fire blight is a tree disease caused by the bacterium Erwinia amylovora.
(Iconic image) © agefotostock/Imago
The fire blight is not easy to spot.
The fruit tree affected by the bacterium shows symptoms such as reddish-brown to black, withered shoots, flowers, leaves and later fruit, especially from June.
Shoot tips bend down like a hook.
In warm, humid weather, droplets of slime sometimes form on the affected branches.
The trunks and branches look as if they have been burned, the bark has caved in, the wood underneath is a bright reddish brown.
Since this type of damage also applies to other pathogens and plant diseases, it is necessary to commission a special laboratory test or consult a specialist from the Plant Protection Office.
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Measures against fire blight on apple trees
An infested tree can infect neighboring trees.
In order to contain fire blight, the Bavarian State Research Center for Agriculture (LfL) therefore recommends the following measures:
Cut the tree: Immediately remove the affected shoots (only in dry weather!), cutting out generously up to about 20 centimeters into the healthy wood.
Disinfect all cutting tools such as scissors and saws with 70 percent alcohol after each cut.
It is best to wear disposable gloves and always disinfect your hands.
If local ordinance allows, clippings can be burned on the spot.
If this is not possible, a small part of the clippings can be disposed of with the residual waste.
Larger quantities should be delivered well covered to a waste incineration plant.
Do not chop the clippings and put them in the compost, as this will allow the pathogen to spread!
Proper tree care is important.
Infested plants must also be checked after the cut so that any fire blight that may occur can be removed immediately.
This also applies to the following year, especially after flowering and in early summer.
Fertilize correctly: The tree must not get too much nitrogen, but an adequate supply of potassium is important.
Older apple trees in particular can ward off fire blight infections and, at least on the outside, become healthy again.
If pruning does not help, the tree must be cleared.
However, the tree protection statutes of the respective communities and the Federal Nature Conservation Act must be observed.