Control procedures

The most effective control measure is for affected trees to be completely removed, or for the leaves to be carefully swept up and incinerated.

This may be difficult for plants in rough herbage or on private land, and must be done before adults emerge - by the end of March (Kehrli and Bacher 2004).


The moth is a major threat to the white-flowered horse-chestnut as an amenity tree and source of conkers for childrens' games (traditional in the UK), but not because it kills the trees.

Attacks have not caused tree mortality in the last 15 years and the trees can still usually produce conkers, although of lesser weight (Thalman et al, 2003). The problem is that councils are increasingly replacing the trees with other species whose aesthetic value is not affected.

This may be unnecessary because horse chestnut trees seem to adjust to heavy attack by increasing the hydraulic efficiency of the wood thus ameliorating the water and the nutrient supply to leaves (Salleo et al, 2003) and may be already adapted to attacks of the moth by photosynthesizing early in the season.

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