You were sitting in your cube or working the line. You hacked. You sneezed. You blew your nose like a trumpeting elephant. You were miserable.
Your co-worker looked over the cubical partition, or across the line and said, "Joe, you ain't worth a broke popsicle stick. You take your butt home before you make the rest of us as miserable as you are."
Therein lay the salvation of hypovirulence.
Two Masses Orbiting
The script for two actors was discussed in Part III. The dynamics of two actors leaves little room for improv.
As humans, we have a vision of a chestnut orchard or a forest dominated by oak. The script in Part III has that orchard or forest living on borrowed time. The increasing density of the hosts changes the selection pressure from "host discovery" to "rapid host exploitation".
Unlike animals, plants do not have an active immune system that develops a portfolio of antibodies with exposure to pathogens. Being exposed to a hypovirulent strain of a disease does not harden the plant against a future exposure to a virulent strain. Increasing density of potential hosts makes catastrophe inevitable and the timing is completely unpredictable.
Economists, planners and bank loan officers do not respond well to unpredictability. It is also emotionally harrowing.
The Third Actor
The trajectories of two masses that are mutually orbiting is mathematically predetermined and offers little drama and little opportunity for human intervention.
Adding a third actor opens up a multitude of potential outcomes because the range of "solutions"
One of my hobbies is homebrewing and home wine making. In the course of pursuing this hobby I stumbled across "Killer Yeast".
In Saccharomyces cerevisiae are toxins encoded by a double-stranded RNA virus, translated to a precursor protein, cleaved and secreted outside of the cells, where they may affect susceptible yeast. There are other killer systems in S. cerevisiae, such as KHR  and KHS  genes encoded on chromosome.
The L-A dsRNA virus of S. cerevisiae...encodes a secreted protein toxin (the killer toxin) and immunity to that toxin. L-A and M are transmitted from cell to cell by the cytoplasmic mixing that occurs in the process of mating. Neither is naturally released from the cell or enters cells by other mechanisms, but the high frequency of yeast mating in nature results in the wide distribution of these viruses in natural isolates.
|Picture from HERE|
Picnic bugs (aka, sap beetles) are the natural vector of Oak Wilt. Picnic bugs are attracted to rotting fruit, presumably by the volatile esters. The fruiting body of the Oak Wilt produces those kinds of attractants. After becoming a carrier of the fungi, the picnic bug feeds on the sap of an open wound, presumably attracted by the byproducts of fermentation. In the event that the open wound is on an oak tree, there is a high probability that wounded tree will become infected.
Picnic bugs are "Bill's" vultures.
At this point, it is speculative to presume that an existing strain of Killer Yeast virus could pass from a yeast bearing culture to a picnic beetle, thence to an infected tree...and debilitating the virulent form of Oak Wilt to where it "ain't worth a broke popsicle stick."
It is entertaining to speculate about. Also, given viruses sloppy replication and rapid mutation, I believe it could be made to happen.
A table of strains of yeast. Column 10, "Competitive Factor" active indicates a "killer yeast".
Attempting to inoculate the picnic bug with killer yeast would involve feeding them with a yeast culture via a sponge sitting in a bowl. It should be in a warm place but out of the sun.