QuestionsHow to growTrees and ShrubsPests and Diseasesbeech hedging 0 Vote Up Vote Down olivia timoney asked 14 years ago We recently planted some young beech hedging which has a white substance growing on the back of the leaf can u give us some advice as what is best to do? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago This is beech aphid and it can weaken a beech hedge significantly. Spray thoroughly with a garden insecticide.