Overview

• Many street trees are already brown well before autumn, with Mainz reporting widespread discoloration and Frankfurt listing about 6,400 horse chestnuts that are largely infested.
• Larvae tunnel within leaves, sharply reducing photosynthesis and triggering premature leaf drop.
• Prompt removal and disposal of fallen leaves can cut overwintering pupae and ease next year’s pressure, with a nationwide community leaf‑collection day set for November 9.
• Repeated infestations weaken trees and heighten susceptibility to bacterial and fungal diseases, a risk intensified by heat and drought stress.
• Insecticides are not approved for home gardens, while pheromone traps are available but costly and labor‑intensive, and natural predators offer only limited control.