Borers are a group of insect pests that spend part of their adult or larval life stage feeding inside roots and branches, or tunneling beneath the bark or into the heartwood of many trees and shrubs. Many species of boring insects are capable of causing internal damage to a wide range of plants. As adults, they may be either beetles or clear-winged moths.
Plant injury caused by borers can be long lasting; moderate to heavy infestation can cause death of the plant. Any plant can be susceptible, but it is generally believed that wood borers are secondary pests that develop because trees and shrubs are stressed, injured, or dying from other causes. Plants most susceptible to borer attack are those stressed from recent transplanting, drought, repeated defoliation, mechanical injury (mowers, grass trimmers), or other causes. (Also see plant information leaflet on bronze birch borer.)