EN
Extract of Polyscias filicifolia suspension culture was used to reduce damage to horse chestnut (Aesculus hippocastanum) leaves by larvae of the horse chestnut leaf miner (Cameraria ohridella). The results showed the repellent effect of biomass extracts on Cameraria ohridella moths. The number of moths caught per day on sticky traps treated with extract was more than 50% lower than the control. The same extract on leaflets caused C. ohridella females to lay ~20% fewer eggs than on leaflets without extract. P. filicifolia extract had a repellent effect on female moths in laboratory conditions as well. Only single mines were observed on leaves treated with P. filicifolia extract, five times less than on control leaves. The data indicate that P. filicifolia extract can be used as a repellent for C. ohridella in springtime when the overwintering generation emerges from pupae.