Answer: I am not sure about "English bees" but I do know that giant hornets (Vespa crabro germana) will remove adjacent strips of bark from lilacs and can girdle branches or trunks and kill them. The damage can be extensive and I suppose if the infestation is heavy enough the plant could be sufficiently weakened so as to be threatened. The hornets feed on the sap and use the strips in their nests. I can think of two methods of dealing with this problem. One is to paint the stems with Sevin early in the season as soon as the activity starts, the other I suppose would be to locate and destroy the nest which is usually easier said than done. The activity should stop for the time being when the weather cools.
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