Whether Ebola infects the blood tube walls directly or causes an immune response that damages them, one of the advanced symptoms is leakage of blood from the tubes or vessels. We know even less about the red blotch virus that is infecting our grape vines except that, like Ebola in humans, it can be found in all parts of the plant. Also like Ebola a signature symptom of red blotch is the damage to leaf veins that causes them to release red anthrocyanins, particularly on the underside of the leaf.
The analogy can only be taken so far. While neither Ebola nor Red Blotch seem to be very efficient transmitters, Red Blotch, which we propose to rename Red Vein Virus after its characteristic symptom, seems rarely fatal to the grapevine. In fact, the late onset of the symptoms in the growing season allows bountiful grape production. It is not yet clear if the late loss of green canopy or asymptomatic processes earlier in the growing season are responsible for the slow ripening, low sugar accumulation, and high acidity in Red Vein Virus affected fruit.
A brief natural history of viruses seems worthwhile. Before life had colonized land, viruses and bacteria and had been battling for hegemony in the oceans for billions of years. Fungi probably entered the fray about 1.5 billion years ago. The bacteria were busy building algal mats and the sort of stuff we might call slime. All the while they had to deal with these terrorists or barbarians we call viruses, yet the competition and genetic accommodation yielded advances. We may very well owe the polymerases of mitochondria which provide the energy for all more complex life, sex, and even photosynthesis to viral innovation.
At a price. Viruses are also prime suspects for mass extinctions and huge swings in ocean chemistry.
With all this in mind, how do we deal with our comparatively trivial problems today? Dr. Sudarshana of USDA and UC Davis says that Red Vein Virus is endemic to California. My suspicion is he is more right than he knows. The results are not yet back but we have found very similar symptoms in wild grape, vitis California, wild blackberry, and possibly poison oak.
Red Vein Viral symptoms in wild Grape emerged in 2014.
Suspicious symptoms in wild blackberry.
We have seen strong circumstantial evidence that Red Vein Virus is now entering vineyards from adjacent woodlands. This would be truly endemic.
We strongly suspect mites as one of the vectors, but their low mobility and strange mid vineyard cases suggest other more mobile vectors as well.
One school of thought is that Ebola is lethal because it elicits an all or nothing cytosine overreaction from the human immune system. Whether or not this is the case, we wonder if the widespread ripping out of infected vineyards may be an exaggerated “immune response” from growers. Relying on clean plant material and slow transmission of the disease may be a bad choice if reinfection from native plants joins infection from ubiquitous infected neighboring vineyards and infected roots left in the soil as agents of the disease.
We may have reached the point where the disease is truly endemic and inevitable. The better choice may be to learn to work with it until resistant stock can be developed.