Remember the classic vascular test used in grade school with food colour and a stalk of celery?
We used phosphorescent blue dye and saturated a drip-zone on a 75-yr old live oak, began detection up 25ft in the canopy in 24hrs on .25" twig samples. It can travel fast or it can creep-up in weeks.
Many factors undermine the science in this. Relative humidity, seasonal norms, extended drought, saturation precipitation, transporation rates and sunlight intensity, time of day (stomata opening), etc.
Some motts of live oak, which generally vegetatively reproduce instead of acorn survival, are genetic clones..a single specie with many stems..so are predispositioned to infection but single-stand trees are more resistant to engrafting being a mode of inoculum.
I've witnessed negative isolation tests for fagacearum only to watch an oak die from wilt in 48 hours. It happens, there are no "norms" as location, stand, altitude, weather all play a role as do more virulent strains of the disease.
Transportation rates of treatment injections also vary, most failing to translocate effectively in the tree or if so, fatally damage xylem and other vascular activity..if they do. The reason I sought alternatives to useless injection. A chemical "girdling" of the tree at the root collar, more often a mortal blow than a therapeutic.
Trenching to distant root grafts had failed 100% in my research..but that was Texas/Oklahoma/Arkansas work..on Quercus fusiformis-virginianna and post oaks/black jacks. Backfilling dripline trenching just invited a mass of new root shooting, regrafting in as short as 2 months. So we NEVER advocated the tool chest the State promoted.
Southern Live or California live oaks are unique...vascular tissue is located well into the heartwood where they can store moisture and survive ten-year droughts. Reds are cursed with thin tissue below the bark but respond better to pre-infection injections. A little.
The mechanism of "tylosis" is vastly different between the two in that reds cannot isolate the endohyphae in each vascular cell that a live oak attempts to do. That's what kills a live oak..they choke themselves to death with a blast of phytoplasm to isolate an infection..but the problem is the disease mutated a response that helps it bore thru or find small punctures in each vascular cell and grows around this metabolic disease response.
See 'systemic acquired resistance' on the net.
Chemical work, specifically propocanazole (Alamo), I claim helped the disease mutate into the killer we fight today. Tissue analysis reveals these trees successfully managed wilt infections in the past. No more, not with oaks anyway.
Restoration work to supplement vital micro-elements and specific triggering nutrients has shown a way to help the tree manage the disease. But methods of treatments are dictated by the state schools, for most of the directed funding came from whoever controlled the ALAMO label-use patent. I found out the hard way.
The enzyme that a Quercus manufactures after a tylosis/codit response to infection is the key to eradicating the effects of this disease. It's naturally present in the xylum and it has a voracious appetite to cerocystis. Someone young with balls and resolve should research this. In the soil, we can introduce either an antagonist or a stimulant to promote this activity in the tree, instead we're trying labelled chems that only suppress it. It's a research proposal instead of a market-driven money maker.
It became political in Texas. It even inspired the label owner at the time (Novartis Chemical/Rainbow Tree Care, Inc.) to lobby for and receive legislation that would criminally prosecute and fine up to $10,000 per tree violation for any alternative treatment other than that recommended by the State of Texas.
That was partly the reason oak wilt became the most costly disease epidemic in the history of American forestry. That would include Dutch-elm, Chesnut blight, and AEB.
Advocating for, and proposing nutritional treatments literally became illegal in Texas, thanks to the monied interests who owned the rights to a deadly invalid chemical label which enjoyed and prospered under political maneuvering.
I enjoyed breaking the law and became proud of being a criminal. The survival rates bare me out.
I might also add that the Vegetable law, which would allow producers or distributors or retailers to quash any public disparagement of products, became a result of our work to discredit the toxic, tree-killing advocacy of a developed fungistat labelled for oak wilt therapeutic..because it not only consistently failed, need increasing dosages for 'effectiveness', costs determined by market demands, and is a carcinogen released without public comment, it simple didn't work.
The vegetable law can be studied by your looking-up Oprah Winfry's legal battle with the Texas Cattleman's Association after she recommended a less-red meat diet. They sued her for millions.
But alerts and common logic should dictate measures in areas not mapped as threatened or active. The guidelines of sanitation have to be seen as the new normal, and cultural changes to ways we've become used to; turf management for monocultered ground covers, nitrogen amendments to be controlled or eliminated (feeding the disease) or movement and storage of diseased tissues/tools. All important and probably should be introduced as laws.
That's conscientious prevention.
Oak wilt can be difficult to diagnose, even by experts. But proper identification is essential for treatment. Veinal necrosis is one of the symptoms that will stand out. For red oaks hardly any treatment is possible, only prevention will help. There are many great tree service companies in Dallas and other parts of Texas that are keeping up with major tree diseases like oak wilt, anthracnose, beetles and more. But only with the help of caring homeowners. This quick and cheap oak wilt test is great, but to know definitively is the best course of action for preserving the tree.