Large-scale leaf miner infestation on Berlin chestnut trees

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  In Berlin, the leaf miner has infested large areas of chestnut trees.

• Chestnuts infested by the leaf miner lose wilted leaves on a large scale as early as mid-August.

Brown leaves on the streets like in the depths of autumn: the leaf miner has already left its mark on Berlin's chestnut trees.

‘Almost all horse chestnuts are affected. You get the feeling it's worse than ever this year. But it's not,’ urban nature expert Derk Ehlert told the German Press Agency. This year, however, the pests are about two to three weeks ahead in their development due to the heat and dryness, explains Ehlert.

Weakened chestnuts can die after moth infestation

The larvae eat away at the leaves and damage the trees. ‘The chestnuts don't die if they are infested with leaf miners,’ says Ehlert. However, it can happen that the trees are already weakened by other influences and die after a moth infestation.

Appeal: Collect leaves consistently

According to Ehlert, it is important to consistently collect the leaves until spring to contain the infestation. This is because the new larvae also sit in discarded leaves and swarm out to the tree after hatching. ‘The fewer eggs and larvae there are in the leaves, the less affected a tree will be next spring,’ emphasised Ehlert. Another natural solution for controlling the moth is tit boxes. This is because tits feed on leaf miners. In individual cases, pheromone traps are also helpful, said Ehlert.

Leaf miner in Berlin since 1997

According to the Plant Protection Agency, the leaf miner was first discovered in Berlin in 1997 and has been present throughout the city since 2002. It originally comes from the Balkans. The leaf feeding of the leaf miner causes so-called mines to develop in the leaves, which first turn light green, then slowly change to brown, curl and fall off prematurely.