Thursday, August 8, 2013

Borers - Bad Bugs that Bring Big Problems for Trees

Many insects feed and make their homes in the bark, trunks and branches of shade trees and shrubs in the Chicagoland area. Summers are hot and insects are just looking for a cool dark place to rest as well as a good food supply - all of which can be found in trees.  

Insect borers belong to several different insect groups including a variety of beetles, moths and horntail wasps. In addition, most insect borers are attracted to weakened, damaged, dying or dead plants. These are referred to as “secondary invaders” because they attack only after a plant has been weakened by another stress. 

Secondary invaders are a symptom of other problems with the health of the tree or shrub, but may contribute to its decline. Secondary invaders include species from groups already mentioned, but also may include termites, carpenter bees and carpenter ants. Many other insects live in dying or dead trees, including natural enemies (predators and parasites) of the insect borers, sap or fungi feeders, or species which merely use the spaces provided by the tunnels and galleries as living quarters. 

On the other hand, there are also primary invaders. These are wood-boring insects that attack healthy trees and shrubs. Primary invaders are much more dangerous than secondary invaders as they may eventually kill trees.

Wood Boring insects often lead to infestations of the insect. Unfortunately, these infestations often go unnoticed until plants or parts of plants begin to die or show external  signs of damage. Which, by then, treatment is much more intense in order to try to save the tree.  In some cases it is too late to save the tree at this point, but always consult with your local arborist for a professional opinion of the condition of your tree. You'd be surprised the condition of trees that can be salvaged. 

A tell-tale sign that your tree has wood boring insects is a sawdust-like frass (excrement). Another sign is the damage to the tree or plant. Their holes are normally round, oval or semicircular and are found in a random pattern on the plant.

Please stay tuned...there's more to come on these borers. The different types of borers and their management will be in my next post. 

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