Managing Wood-Boring Insects

To keep your trees healthy, one will want to watch out for what is called wood-boring insects. These insects are considered secondary invaders, which means if your tree is already unhealthy, infestation of these insects will only damage them more. So what can you do to avoid these wood-boring creatures? According to the local extension agency, here are a few good horticultural practices:

• Select well-adapted species of trees and shrubs that are not commonly attacked by woodborers in your area. Arizona ash, birch, cottonwood, locust, soft maple, flowering stone fruits (such as peaches and plums), slash pines (in west Texas), willow and poplar are especially prone to borer attack.
• Choose and prepare a good planting site to avoid plant stress, freeze damage, sunscald and windburn.
• Minimize plant stress and use proper watering and fertilization practices.
• Avoid injury to tree trunks from lawn mowers, weed trimmers or construction. 
• Promptly care for wounded or broken plant parts using pruning or wound paint during all but the coldest months of the year.
• Properly thin and prune during colder months.
• Remove and destroy infested, dying or dead plants or plant parts, including fallen limbs.
• Wrap 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. Sometimes wrapping trunks to prevent borer attack is ineffective and may, under certain conditions, increase the rate of infestation. Using plastic trunk protectors to help prevent injury from lawn mowers and weed trimmers is a good idea.

So what about the use of pesticides, you may ask? Once trees and shrubs are infested, non-chemical options for borer control are limited. One option is to remove and destroy heavily infested or injured plants. Damage sites also can be inspected closely to determine if the larvae stages can be extracted from the plant with a pocketknife, wire or other suitable tool.   Again, it is important to remember that stressed, unhealthy trees can be attacked repeatedly and will need repeated applications of insecticide indefinitely. In most cases this is neither economical nor environmentally justified. When chemical treatments are used, efforts always should be made to improve overall tree health.

Insecticide products registered for borer control are applied as sprays to the trunks and branches, and are non-systemic, residual insecticides (e.g., bendiocarb, carbaryl, chlorpyrifos, endosulfan, es-fenvalerate, f luvalinate, lin-dane, methoxychlor, sumithion). While these products do not kill larvae that have already penetrated the sapwood or heartwood, they will kill adult and larval stages tunneling through the treated bark layer. These are primarily a preventive treatment. Some products (those containing paradichlorobenzene and ethylene dichloride) act as fumigants to repel egg-laying adults or kill accessible larvae.  

Trunk injection products (containing acephate, dicrotophos and oxydemeton-methyl) are registered for treatment of some borers. These products are supposed to work by delivering insecticides into the cambium and phloem tissues where borers feed. These injections are most effective against sap feeding insects and rarely affect woodborer larvae. Research has shown that damage caused by inserting the injection devices into trunks can be significant.

One way to protect your trees is to consider where these wood boring insects are coming from. Most adult woodborers emerge from firewood stored indoors. While most of these insects are not considered harmful, old house borer and powderpost beetles will attack seasoned, dry wood inside the home. Treating firewood with insecticide is both ineffective and potentially dangerous to the homeowner. Wood should be stored outdoors away from the house until just before use. If firewood is infested with borers it can be treated by wrapping it in a tarp and allowing sunlight to heat it. Stacking wood layers in alternate directions will help it dry and reduce areas that can harbor insects.

By practicing these few things, you could save yourself a lot of time and money in protecting your trees.
Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.

Your Trees’ Basic Needs

The number one need is water. If you have just planted a tree in your yard, the first thing it needs is to be watered. Hose the base area and then dig a little trench in the topsoil around the base. Leave your hose just trickle a bit in the trench for awhile so it can get a good soaking first time in its new spot. Newly planted trees should be watered at the time of planting and every day for the first week. Then during the first growing season, they should be watered at least once a week in the absence of rain and more often during the height of the summer. However, be careful not to over water them. This will result in oxygen deprivation and they can die if over watered.

As a general rule, regular deep soakings are better than frequent light wettings. To encourage the roots to grow and the tree to be strong, the moisture from watering should reach a depth of 12 to 18 inches below the soil surface growth. If you are not sure if you should water or not, you can just dig down about 6 to 8 inches at the edge of the planting hole. If you feel powdery or crumbly dirt, water the tree. If you can squeeze the soil into a ball, the tree has enough moisture.

There also is available a soil additive that manages the water around the root structure. This additive contains super absorbent gel polymer crystals that absorb hundreds of times their weight in water. When the tree is watered, these crystals absorb the moisture and release it again for the roots to use when the surrounding soil becomes drier.

Trees and shrubs face a number of stresses that lead to a decreased lifespan. Providing consistent and adequate water to the root systems will go help to decrease tree stress and promote growth.

Next, the trees need mulch. To conserve moisture, promoting water and air penetration, the soil surrounding newly planted trees can be covered with mulch consisting of material such as bark, wood chips or pine needles. Because pine needles have a high acidity content, they should not be used around certain plants. Mulch depth should be between 3 to 4 inches. Only porous landscape fabric should be used to cover the area surrounding a tree since it freely allows water and air penetration. Plastic sheeting will prevent this from happening. If you want to stop weeds from growing on a path way, use the plastic sheeting there before spreading down your choice of path covering.

And the last basic need is fertilizer. It can be beneficial to get your soil analyzed to see how much macronutrients are in it already, such as Nitrogen (N), Phosphorus (P) and Potassium (K), pH, and micronutrients. If there is a noticeable imbalance, fertilizing when planting can help out. The majority of plants suffer root loss and stress when they travel from ideal nursery growing conditions to the final planting in your yard. So it is best to add some fertilizer at the time of planting to ease the transplant shock. Treat your trees with mycorrhizal fungi and fertilizers with the right formulation for the type of tree you are planting. A biostimulant can boost root development and aid in the general health of the tree.

Water, mulch, and fertilize your trees. These are your trees’ basic needs. With the proper tree care your trees will live a long and healthy life.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading Austin Texas tree service provider in Central Texas (Travis County and surrounding areas). Central Texas Tree Care offers services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management and fertilization. For more information please visit http://www.centraltexastreecare.com.