Dead oak tree

Asked November 30, 2014, 6:35 AM EST

I have an oak three that was coming out in the spring and the leaves never completely came out. This is a very old tree with a small oak right next to it. They both died during the summer (July- August) I had a tree cutter cut it down yesterday and there were small white looking worms in the trunk- limbs of the tree. It looked like grubs. I don't want to lose any more trees. What is this and do I need to treat the ground where these trees were? I have 6 other oak trees in my front yard that appear healthy. Thanks for your help I took a picture with my cell phone.

Brazos County Texas trees and shrubs horticulture

1 Response

I do not see the attached picture.

The grub looking insects are larvae of various beetles we call borers.

Many insects feed and make their homes in the bark, trunks and branches of shade trees and shrubs in Texas. Insect borers belong to several different insect groups including a variety of beetles, moths and horntail wasps.

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.

Wood-boring insects that attack healthy trees and shrubs are called “primary invaders.” Primary invaders may eventually kill trees.

Damage

Borer infestations often go unnoticed until plants or parts of plants begin to die or show external signs of damage. Wood-boring insects often produce sawdust-like frass (excrement). Their holes are normally round, oval or semicircular and are found in a random pattern on the plant. Woodpecker damage is sometimes confused with that of wood-boring beetles, however woodpecker damage will not produce frass. One woodpecker, the yellow-bellied sapsucker, produces square holes in rows around a trunk or branch.

Many borers damage plants by tunneling through the inner bark layer (cambium) into the sapwood (xylem) that transports nutrients and water to the leaves. These insects are called phloem feeders. When the cambium layer is completely girdled the plant eventually dies above or beyond the damage site. Partial girdling reduces plant growth and vigor above the site of attack. On occasion, tunneling makes the tree weak, causing limbs and branches to fall. Borer damage can severely affect the quality of lumber and can make trees susceptible to disease.

Managing Wood-boring Insects

Prevention

Since most wood-boring insects are considered secondary invaders, the first line of defense against infestation is to keep plants healthy. Proper care of trees and shrubs discourages many borer pests and helps infested plants survive. Good sap f low from healthy, vigorously growing trees, for example, defends the plant from damage by many borer pests. Good horticultural practices include:

  • Selecting well adapted species of trees and shrubs that are not commonly attacked by wood borers in your area. Arizona ash, birch, cottonwood, locust, soft maple, f lowering stone fruits (such as peaches and plums), slash pines (in west Texas), willow and poplar are especially prone to borer attack.
  • Choosing and preparing a good planting site to avoid plant stress, freeze damage, sun scald and wind burn.
  • Minimizing plant stress and stimulating growth by using proper watering and fertilization practices.
  • Avoiding injury to tree trunks from lawn mowers, weed trimmers or construction.
  • Promptly caring for wounded or broken plant parts using pruning or wound paint during all but the coldest months of the year.
  • Properly thinning and pruning during colder months.
  • Removing and destroying infested, dying or dead plants or plant parts, including fallen limbs.
  • Wrapping tree trunks and limbs with quarter-inch hardware cloth spaced about 1 1/2 inches from the tree’s surface where woodpecker damage is likely.
To learn more go to
https://insects.tamu.edu/extension/bulletins/b-5086.html
http://texasforestservice.tamu.edu/main/article.aspx?id=1209