Oak Wilt - The Injection Process
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The Root Flare Injection Process
First expose the buttress roots or root flare of the tree or trees being injected. This is accomplished with careful excavation of the base of the tree where plant material and soil are removed from around the base of the tree. The distance away from the trunk in which plant material and soil will need to be removed will vary according to the size or diameter of the tree being treated. Hand digging tools are the usual choice to clean out around the trees. We use an air gun as illustrated below using our Grimmer Schmidt 185 DR air compressor that produces 150 psi. The supersonic nozzel directs a lazar like beam of air near 1000 mph, which allows for fast safe ecvavation even in hard soils. unlike digging tool, the air does not damage the root flares.
The second step is to physically perform the high water volume root flare injection with the registered fungicide " KESTREL", Quali-Pro or Alamo Propiconazole 14.3% MEC . These are presently (but not limited to) the only products registered and labeled for this purpose. They are available in a water-soluble formulation, "KESTREL" and Quail- Pro is an amber color. A dye can be added to help identify any leakes. Anything else being used is ineffective or being illegally applied. (see Oak Wilt Bulletin - Off Label use of Alamo like Products )
Quali Pro Propiconazole 14.3 % became availabe in April 2005 and "KESTREL " Propiconazole 14.3 % MEC, in January 2006 at a more reasonable cost and have proven to be very effective for treating Oak Wilt. The research by Dr. David Appel from Texas A&M University was conducting on Qual- Pro Propiconazole efficacy. Tests with different concentrations of the fungicide and was added to Ceratocystis fagacearum. The test results showed that the fungicide was fungitoxic to C. fagacearum to the lowest concentration of Quali-Pro was 6 parts per billion (6 ppb). The research technician's analysis stated that it seemed to be more fungitoxic than Alamo.
A series of portals will be drilled up and down the exposed root flares at about 3-4 inch increments. The greater number of portals the better the distribution around the tree. Proper location of these injection sites is critical for proper distribution of the fungicide. Inadequate distribution leaves trees poorly protected. A series of injection tees are inserted into the injection sites and connected with tubing call a harness to create a closed system. The system is usually attached to a pressure tank containing the fungicide solution and the injection process begins. The healthier the tree the quicker the uptake of the fungicide. (See Water movement in Trees) Once the tree has taken up the allotted amount of fungicide, the system is broken down and removed from the tree. Fill in the exposed area around the tree with the excavated soil. There will be many instances where trees have been planted too deep, or fill soil has been brought in. In these cases we will commonly recommend to leave the root flare exposed entirely. Each situation will differ and your Arborist will recommend what is best for the long-term health of the tree.
In general, Live Oaks and Red Oaks not expressing active disease symptoms are good candidates for preventive root flare injection with the fungicide. The ingestation period for the oak wild disease is normally 4-6 months. It appears that Oaks can be infected with the fungus up to a year before active symptoms are expressed. What this means is that an apparently healthy Oak adjacent to a diseased tree may already be infected and in this instance, uptake of the fungicide may be poor. Treating infected Texas Red Oaks or The Spanish Oak, with the fungicide is totally ineffective and a waste of time and money.
Frequently Asked Questions Regarding
Flare Root Injections With " KESTREL" :
Why does the process seem expensive?
The cost of the process is primarily driven from the cost of the fungicide. This is dictated by the manufacturer and distributor. The amount of fungicide used in the application of 10 mils. and 20 mils. dosage respective per diameter inch also relates these higher costs. There is also the cost of the injection equipment, quite extensive labor involved in properly exposing the root flare of a tree or trees, and the injection procedure and monitoring the process itself until the job is completed. As an added precaution, we strongly recommend the 20 mil dosage for trees over 20 inches in diameter due to their size and mass. However, now that the Alamo patent has expired " KESTREL " and Quali-Pro Propiconazole 14.3% MEC are now available and prices may very well stabilize.
Does it matter how much fungicide the tree receives?
It is critical that the tree receives a minimum of 10 milliliters of Kestrel, for every inch in diameter as a preventive application. High dollar value or high risk trees near the oak wilt center, it is recommended to apply the therapeutic dosage rate of 15 to 20 mils./dia. inch. We strongly recommend applying the higher dosage rate of 20 mils. for the very large trees, and trees that are at the most risk from the disease.This is a margin of safety for reason of their high dollar value, size and strength of the disease pressure in the area. This Diameter measurement is usually taken 4.5 feet from the soil grade. Injecting symptomatic trees, the success is somewhat diminished by the extent or degree of the infection.
A WORD OF CAUTION HERE: We all have the tendency to think, that more is better, so lets just boost the dosage rates to say 30 mils per diameter inch. Really, nothing could happen, if 20 mils is good then 30 mils has to be even better. WRONG..... Texas summers are usually hot and dry. However, severe phytotoxicity plays a serious factor here. This combination of hot - dry weather and the therapeutic dosage of propiconazole can ZAP a tree, quicker than Oak Wilt. I mean that it will turn every leaf on your tree brown, .... DEAD......and literly over night. The therapeutic dosage rate of 20 mils per diameter inch can will have the same effect on smaller diameter trees of 6 inches or less, when treated early in the growing season. Propiconazole has to have a high volume of water as the carrier for proper distribution throughout the tree and the uptake is usually relatively fast. Proipconazole has a near pH balance, and there is less tissue injury at the injection site. However under certain conditions as described above, apply the higher dosages rates with guarded caution. We strongly recommend strict compliance as prescribed by the product label.
Which trees should I treat?
Your Arborist will generally recommend to treat the Oaks that are adjacent to the infected trees, establishing a parameter around the oak wilt center. This will vary from site to site and will usually include trees already showing active symptoms.
How fast does the disease spread in a population of Oak trees?
The disease has been reported to move up to 100 feet per year through their roots systems in a solid stand of Oaks. This can vary greatly due to variables unique to each site. Live Oaks only spread the disease through their interconnected root systems. The beetle is responsible for long distance transport of the fungal spores.
Should my neighbor treat their trees
The best candidates for preventive injections are those Oaks out ahead of the active disease center. Trees should be treated within 150 feet of the out break. Trees showing active symptoms of Oak Wilt are some what more difficult to save. The expectation of the fungicide, to do much more than it is designed to do when we are always treating trees adjacent to infected trees. Alamo can extend the life of your trees, but it cannot resurrect the dead or revive the badly infected trees. To safeguard the value of your property and your trees, it is important to treat preventively, than to wait for your trees to become infected and then take action. It then becomes difficult, if not impossible to stop the disease and you may very well lose one or several high dollar value trees in the process. Treat your trees before you suspect you may have oak wilt.
Is this injection process guaranteed?
The process has no guarantee. However, the success rate can be 90-100% for treating trees that are disease free and not showing active symptoms. We have had very good results with high volume root flare injection to date. We still see failures from time to time, which is usually due to the tree already being infected which leads to poor uptake and distribution. Current research suggests treating in two consecutive years may give the best results. If the disease persists in the area and treated trees are still considered at risk, subsequent treatments should be considered.
Are there alternative methods for the prevention of Oak Wilt?
NO, there are other types of injection, such as "microinjection" ( see Microinjection article ) which has no data to date that suggest any type of control or prevention. This process is strictly experimental and will take a number of years to provide adequate data one way or the other. DO NOT LET anyone tell you differently. This can be a confusing point because the manufacturer has packaged Alamo in a microinjection system. This was done primarily to increase revenue for the chemical company, and the applicator, in order that may appear to be a quicker and easier method of injection. The so call other alternatives of spraying trees with bio-stimulants, plant extracts, plant sugars, water and fertilizers is another get rich scheme at the expense of your trees. ( see Oak Wilt Treatments / Bio-stimulants and TREELIFE "The New Cure for Oak Wilt" articles ). These type of applicators, need very serious legal council and a great deal of scientific council.
If I keep my trees healthy will they be less susceptible to infection by the Oak Wilt fungus?
No, it is unfortunate that this is not the case. We are dealing with an aggressive vascular wilt disease and a tree, which is genetically predisposed to infection by the fungus. To draw an analogy, the Measles Virus does not infect children, which are unhealthy. The healthiest children will still get the infection at some time or another because humans are genetically predisposed to the Measles Virus. The same goes with the oak wilt fungus, it infects healthy trees and the healthier the tree, the faster the infection moves within the tree. The oak being pruned at the wrong time of the year and should be done in the heat of the summer or cold of the winter. Sterilization of pruning instruments is another wise precaution with oak wilt and painting wounds with a light coating of a spray paint rather that using heavy pruning paints. You want to protect the wound from the beetle, but allow the wood to cure naturally.
Will the root flare injection ever need to be repeated?
Once trees are injected, it appears they are protected for about 2 years. If disease pressure is high, that is to say the Oak Wilt center is still active next door or across the street, we may recommend to retreat the following year. If we are treating trees with active symptoms and the symptoms reappear the following season, we will commonly recommend to retreat. Retreating high dollar value, unique or historic trees annually as a preventative is not unusual. After two year there is no longer residual fungicide found in the tree and the new growth rings should also be protected.
What about trenching?
Trenching plays a key roll in the oak wilt suppression program, it is designed to circumvent the disease center disrupting the interconnected tree roots. Approximately 70 percent of all the oak wilt trenches installed statewide have held the disease in check, but it is important to understand that trenching will never stop or slow the spread of oak wilt in the live oak trees. In the past 15 plus years Austin has increased from 70 to over 500 oak wilt centers. That represents over a 400 per cent increase in the disease out breaks. However, the beetle is not looking for stop signs or trenches, just the next meal. The above-ground spread of oak wilt from sap-feeding beetles is a critical factor in the establishment of new disease centers. Beetles can carry the deadly fungus to fresh wounds.
In some cases it is not possible to install trenches. It becomes necessary to inject high dollar value trees to create a barrier in-order protect other trees and stop the progression of the disease. Annual re-treatment of these trees is recommended, as it takes about three years for a tree to recuperate under perfect conditions. Some trees are just beyond saving at the time of treatment. However, some of the treated trees in the yard will survive. You can also lose some of the otherwise survivable, treated trees, if they aren’t watered during hot and dry summers. It is important to deep water during these periods of drought to help survival and recovery.
The Measure of a Tree
Since the beginning of time, throughout the entire world forests, all trees intentionally grow under stressful conditions. Every climatic region and climatic eco-system will challenge and test a tree's ability to grow and survive. In all our forests, survival and time is what Ancient Champion Trees really are made of !
Your Ancient Live Oaks measure time in centuries, not in years ! and ....
They are a non renewable resource of energy.