Insect Borers of Trees, Shrubs

Posted by on Jun 2, 2016 in Blog | No Comments

Wood-boring insects are among the most destructive pests of ornamental trees and shrubs. Most borers are the larvae (immature stages) of certain moths and beetles. They tunnel and feed under the bark in living wood, destroying water- and sap-conducting tissues. This causes girdling, branch dieback, structural weakness, and decline and eventual death of susceptible plants. Infestation sites also provide entry points for plant pathogens.

Clearwing and flatheaded borers are the main types that attack woody ornamentals. The groups differ somewhat in their habits and host preferences, which can affect the approach for managing them with insect control products. The keys to controlling these pests are to keep plants healthy and, if necessary, to treat during those times of the year when the insects are vulnerable to treatment.

Infestation and Damage. Borers rarely infest healthy plants growing in their natural environments. However, when trees or shrubs are transplanted into the landscape, stresses such as drought, soil compaction, sun scald, or injuries can weaken them and make them more susceptible to attack. Adults may locate suitable egg-laying sites by responding to stressed trees.

Adult borers emerge from infested trees in the spring or summer. After mating, the females fly to a suitable host and lay eggs on the bark, often in crevices or around wounds. Hatching occurs about 10 days to 2 weeks later. The young larvae quickly tunnel beneath the bark where they feed and grow. Once inside the tree, borer larvae are no longer vulnerable to insecticide sprays and are seldom detected until serious damage has been done. – Excerpted from the University of Kentucky.

Call Crowleys if you have a concern about pests in your landscape plants.

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