Ecosystem Health > Insect Pests

Insects are vital to the health of plants and animals although only a fraction of the insects active in the environment are noticeable to the casual observer. It is for this and many other reasons that integrated pest management methods be used in dealing with insects. Like the term “weeds”, insect pests should be reserved for those insects causing unreasonable problems to the products we are trying to produce.

Integrated Pest Management (IPM) relies on a combination of common-sense practices which take an effective and environmentally sensitive approach.  In agricultural and forestry settings, IPM takes advantage of pesticide application, mechanical methods, and biological methods.  Sometimes the most economical approach can be no control at all.  As insect pests are discussed for trees, range, and crop damage, please follow the four steps of IPM.  These include: Set Action Thresholds, Monitor and Identify Pests, Prevention, and Control.

Tree and Forest Pests

Most people think that wildfires cause most of the tree mortality in our forests.  A study of forest tree mortality factors indicates that in the United States, insects account for 41% and diseases cause 26% of the tree mortality.  Put another way, insects and diseases together are responsible for killing two out of every three trees that die in our nation's forests.  In general, with respect to insect and disease pests, keep in mind that healthy trees are usually much less susceptible to pest damage.  Especially in urban areas, many times it is the activities of people that compromise the health of trees and make them vulnerable to insects and diseases. 

Commonly classified as defoliators or borers, defoliator insects often either attack a tree's food source (the leaves) and borer insects attack a tree's water and nutrient transport system (between the bark and the wood).  Many insects also feed on wood; however, this usually happens on already sick, dying or dead trees.  A final category of problem insects could be called transporters.  The main example of this is the nitidulid beetle which carries the Oak Wilt fungus on its body.  The beetle leaves an Oak Wilt infected red oak with fungal spores on its body.  It then flies to a healthy oak starting a new disease center.

With an expanding global economy, the likelihood of importing (or exporting) forest pests is greatly increased.  Gypsy moth was imported from Europe around 1870 and has become a serious defoliator of eastern hardwood trees.  More recently, the Asian longhorned beetle (from China) has caused the death of many trees in New York City and Chicago.  Other imported forest pests, like the pine shoot beetle and the emerald ash borer, are causing concern in other parts of the United States and are literally knocking on the door of Texas.  If you come across an insect or disease you can't identify or observe the unexpected death of native trees (particularly ash or walnut trees), please contact the Texas Forest Service office or county extension agent in your area.  You may be the first to detect an unwanted invasive insect.