If your chestnut develops brown spots on the leaves or even the whole leaves turn brown, then it is high time to examine the tree thoroughly. He is probably suffering from pests or a disease and should be treated urgently.
Brown spots are mostly caused by the horse chestnut leaf miner
Where are the brown spots coming from?
The simplest cause of brown-spotted leaves is simple sunburn. Even if the chestnut likes a sunny spot, it can suffer from too much sun, especially if the sunshine leads to a prolonged drought.
Brown spots on the leaves of your chestnut may be caused by the horse chestnut leaf miner, or said their larvae. These eat tunnels, so-called mines, in the leaves. This interrupts the supply of water and nutrients and the foliage withers prematurely. Although the affected chestnut does not die, it is significantly weakened. The harvest is lower and the chestnut is more susceptible to other diseases and pests.
Browning of the leaves also leads to a discoloration of the leaves of a chestnut. This is due to a fungal infection. Responsible is the Guignardia aesculi. The spots can be several centimeters in size and are reddish brown with a light yellow border. If the infestation is severe, the withered leaves curl up, which has also given the disease the name "rolling disease".
Possible causes of brown spots:
- horse chestnut leaf miner
- sunburn
- Leaf blotch (Guignardia aesculi fungal infection)
How can I save my chestnut?
In the current year you can only help your chestnut a little. But prevention and containment of the disease for the next year is possible and strongly recommended. This is the only way to protect your chestnut in the long term.
To do this, collect the fallen leaves before the larvae of the horse chestnut leaf miner can retreat into the ground or the fungus spores of the Guignardia aesculi can spread in the soil. Dispose of the leaves reliably, it is best to burn them. The pathogens can also survive in the compost if the core temperature does not reach at least 60 °C.
tips
Infected foliage does not belong in the compost. There, both the larvae of the horse chestnut leaf miner and the spores of Guignardia aesculi could survive and infest other trees.