Arboricultural Systems Integration

WARNING! ALERT! WARNING!

This artic freeze may damage your trees, landscape, and turf! If possible, water deeply tomorrow when the temps get above freezing. Hopefully your irrigation system has a ‘drain down’ feature. But what is more valuable? Your entire landscape or you irrigation hoses and pipes?

In the winter of 1983-’84, we had subzero temps every night for two weeks in much of North Texas. The most susceptible high value plants that were damaged were our Live Oaks (Quercus virginiana). The bark sloughed off many of the trees, just above grade on the south side. Far too many people listened to uneducated doorknockers and had their Live Oaks removed. You see, we are north of the native range of Live Oaks, so they are more challenged by colder than normal winters.

Our clients listened to us and we waited and watched to see how the trees responded. We discovered that Live Oaks can move undifferentiated tissue to new locations. They produced new cambial tissue and began building new sapwood! Our clients’ trees benefited from additional nutrients, and some prophylactic insect treatments, but they all survived. Our clients also followed our watering directions.

You see, soil can reach ambient air temperature. Monday we are looking at ONE to FIVE degrees above zero. At that temperature, ice crystals form and pe*****te cell walls. Freeze an orange, and then thaw it out, to see what happens to internal tissues. If the soil is damp, then the temperature does not fall below 32 degrees. The root systems of most of our landscape grasses, ground covers, and woody stemmed plants (trees and shrubs) can withstand this.

Stan Randall
Staff Arboriculturist
ARBORICULTURAL SYSTEMS INTEGRATION
2287 South FM 549 Rockwall, TX 75032
http://www.arboricultural.com/
Email: [email protected]
972-772-5314 (Metroplex)
903-439-5565 (Cell)

Arborist, Arboricultural Systems Integration DFW Metroplex, TX Home The Tree Preservation Professionals who can recognized tree diseases, insects, and cultivation issues that may cost you a valuable tree.

Carpenterworm (Prionoxystus robiniae)

This pest may be the single most destructive individual found within a tree. While other insects do their damage via numbers, this single larva may destroy a tree without assistance. But sometimes several hatch and succeed in entering the tree. Only a few eggs are laid by a moth on a tree. One or more of the hatched worms may enter the three and bore deeply into the tree.

Generally, it is thought that the worm goes to the heartwood. However, examination of photos sorted by region indicate it may go towards the heartwood in colder regions, where thicker insulation is required for larval survival at lower temperatures. But trees we have examined in North and Northeast Texas indicate at higher feeding rate is concentrated in the sapwood. And of course in younger trees, as our photos illustrate, there just isn’t a lot of heartwood.

This is a large larva. Some I have found were over half an inch in diameter. So they not only interrupt the flow of nutrients and water, but actually destroy the strength of limbs, or the trunks of smaller trees. They can kill. And of course secondary pests and disease can gain quick access to the interior of the tree thanks to this pest.

We can control them. Our injection of a control agent into the sapwood of a tree kills all internal parasites quickly as they consume the tree’s tissues. So we eliminate this pest, as well as its smaller relatives.

This pest does not present a glaringly obvious problem. A borer infestation reveals itself with multiple weep holes exuding sap. This one may have just a tiny entry hole produced when it was very small. But that is adequate for an air supply. When it exits the tree, we then see a much larger diameter hole. Unfortunately, the adult female may lay her eggs right back in the same tree, driving the population of her destructive progeny up past the level that the tree can tolerate. And if this happens several years in a row, the tree may expire without warning as too much sapwood is interrupted or destroyed. So control measures should be instituted as soon as possible.

We do have some strong evidence that these pests tend to target stressed trees, therefore we must avoid cultural challenges or factors that predispose the trees to such invasions. We don’t want to treat the tree many years into the future, but rather correct the cultural deficits.