Soon after oak wilt was identified in Texas, a program was initiated in the Department of Plant Pathology and Microbiology at Texas A&M University to develop a management program for this major oak disease. The program utilizes both cultural and chemical approaches to disease management. The chemical approach uses a fungicide that effectively controls the fungus. The technique for application of the product has also been developed.

University researchers, extension specialists, members of the Texas Forest Service, arborists and property owners were all involved in evaluating potential pesticides. Candidate compounds were applied in many different ways: foliar sprays, soil drenches, and tree injections. It was not until the early 1980s that a fungicide containing Propiconazole (the active ingredient in Alamo®) injected into symptomatic and non-symptomatic trees was found to be effective in controlling symptom expression.

Many years of field application has proven that Alamo® when applied via Macro Flare Root Injection continues to be an effective weapon in our oak wilt management program. Trees that are not infected but will be challenged by the fungus in the next 12 months are the best candidates for treatment. Trees within 100 feet of a disease tree benefit the most from treatment. Infected trees in early stages of symptom expression can be treated, but their chance of recovery is less than trees that have not be exposed to the fungus. Although trees with early symptoms have a lesser chance of complete recovery, high value trees that hold a special place in the family may have a higher treatment priority.

The Texas Forest Service has utilized aerial photography to determine the growth of oak wilt disease centers. The advancement of the disease averages 75 feet per year. However, there are wide variations of disease spread. Many centers expand faster or slower than the average. In addition, the disease movement is often not uniform. Successful treatments have been made in almost every month of the year. The longer treatment is delayed, the more trees are lost or severly damaged.

Alamo® is a systemic fungicide approved by the EPA for the control of the pathogen that causes oak wilt. Systemic means that the fungicide is most effective when present throughout the tree. The active ingredient is Propiconazole in a water based suspension. There are several formulations of Propiconazole, but Alamo® (and several generic versions) is the only formulation approved for tree injection. It was developed by Novartis. The high volume or Macro Flare Root Injection method using Alamo® is recommended by the Department of Plant Pathology and Microbiology at Texas A&M University. This method has been used successfully for many years.

Dosage is based on tree size. For most Live Oaks, we use 20ml of Alamo® per inch of DBH (diameter at breast height) in up to one liter of water. For smaller trees, a dosage of 10ml may be appropriate. Our company is highly experienced at determining the proper dosage and amount of water mix to apply to your trees.

Proper tree care is essential following treatment. Trees should be watered as needed, possibly treated with a growth regulator such as Cambistat®, and mulched. These practices do not control the disease, but are important to promoting tree health.