Posts Tagged ‘trees’

The female moth actually lays the eggs on the underside of the leaf in early May after the tree leafs out.  The larvae hatch and build a web for protection, then begin to consume the foliage.  The webs expand as the worms increase their intake of foliage.  The feeding lasts about 2-3 weeks until they leave the tree and pupate.  The female emerges and the cycle can repeat 5 times a year requiring a different spray each time.  They do not move from tree to tree, as they only feed in the tree that the worms hatch from.  They generally cause no permanent damage, but we treat often because the client considers it a nuisance.

Save the date!

SEPTEMBER 25

TREES FOR THE TEXAS LANDSCAPE: Selection, Placement, Planting and Care

9:00 A.M. - 1 P.M.

Join  Steve Houser, Consulting Arborist with Arborilogical Services, Inc., the Tree Care Experts, in a discussion of how to select, locate, correctly plant, and care for trees in your own landscape, with a focus on Texas native trees.

FREE PROGRAM | RSVP CALL 214-309-5800

A Significant Root Pathogen

Ganoderma lucidins, the varnish fungus, is a pathogen that enters openings in root systems of many tree and shrub species. In our region, Red Oak, Cedar Elm, Pecan, Live Oak, Pears, and Photinia have all been reported to be species commonly infected by this fungus.

The entry points can be from any activity that damages or severs a plants root system. The fungus lives in the soil as a saprophyte, that is to say, it can live on dead organic matter with no ill effects until it encounters live roots that have been cut.

Published literature, archaic as it may be, suggests the fungus colonizes a plants root system slowly and may take several years, 10-20 has been proposed, to finally kill a tree or shrub. Some have theorized that is might just be a natural component of many old tree species.  We feel that it may be quite a bit more aggressive than first thought. Regardless of the pathogens history, it causes significant damage to our shade trees by destroying a trees structural root system.

Trees have two primary root systems. The structural root system is responsible for anchoring a tree to the earth. A trees fine feeder root system is responsible for the daily demands of moisture and nutrients. Once the structural root system has been compromised, a trees stability becomes quite a concern. Often, trees that fail during storms show evidence of colonization by Ganoderma sp.

The fungus will produce a fruiting structure, a fungal conk, near the base of the tree. It is a shelf like structure that varies in color from a rusty orange-red to a dark red with cream coloration almost always shiny in appearance. The concern is that once the fruiting structure is evident, the fungus has often destroyed a large part of the trees ability to stay anchored to the earth, thus creating a high potential for failure and a potentially dangerous situation.

The difficulty is that above ground signs can mimic other problems. Trees infected with Ganoderma sp. often leaf out in the spring with significant dieback and large dead branches with no changes in the trees environment. Tree owners will often report that the tree looked fine last fall. Even at this stage of the infection, there may be no visual evidence, a fungal conk, apparent at the base of the tree. There is also the opposite scenario in that a trees canopy looks perfectly fine, but fruiting structures have developed. In either case, further investigation may be recommended. These recommendations should never include anything that is proposed to help or control the infection. Recommendations should be to immediately investigate a potion of the trees below ground structural root system to determine the extent of structural root loss.

The sad conclusion is that there is no prevention or control once a root system has been colonized. There is obviously the avoidance of root damage of any type, which is very unlikely in the urban environment. The positive aspect is that after investigation, immediate removal is not always necessary. It does give your Certified Arborist a baseline mark to make appropriate recommendations regarding a potential timeline for removal and replacement.

This is not anything new to our urban forest, nor is it any type of epidemic that all susceptible tree and plant species will die from. It is a serious concern if a large.

by Kevin Bassett and Russell N. Peters

Dormant oil applications to trees and shrubs can be a quite effective tool when managing many of our insect and disease problems.

The application is done once a year during the dormant season. In our area this is roughly January through Mid March. Many times Dormant Oil applications are used in conjunction with other foliar sprays, such as fungicide sprays for the management of fungal leaf diseases. The Oil helps reduce the levels of pathogenic fungi that can “over winter” (survive) in bark fissures and leaf scales or unopened buds. The Oil alone does not provide control, additional spray applications with an approved fungicide will need to be done in the spring after the tree begins to leaf out.

Dormant Oil applications are quite effective against “over wintering” insect pests. Many of our early season pest problems can be reduced with Oil applications. We need to mention again that the Oil alone does not always provide complete management. Additional foliar applications with an approved miticide or insecticide may need to be scheduled for a complete management program.

A particular insect pest that Dormant Oil is especially effective against is the various scale infestations we get in North Texas. If you own Red Oak, Live Oak, Pecan, or Silver Maple, you can find one of the various scale species. Sometimes the level of infestation may not warrant an application. However, this pest can increase in severity quite quickly. Many times it’s best to include Dormant Oil applications as part of an overall health management program. Applications on an annual basis will help to keep scale populations below damaging levels.

The material is a very finely refined oil product, with practically no odor, which acts to suffocate the “over wintering” target pest. It is by far one of the safest products used in pest management.

Many times you may find us recommending the Dormant Oil application to include your shrubs. For example, there are a variety of scale problems which Oil applications can reduce, especially on Holly sp.

NOTE: If you own a swimming pool and we are applying Dormant Oil to trees and or shrubs near the pool, you may experience a cloudy look to the pool when we are done. This phenomenon is temporary and does not damage the pool or filter. It will dissipate in 24 – 48 hours. It is also completely safe to swim under these conditions as well.