Although I am not sure what the case at hand has to do with phytoplasmas, I thought I might post a link to this paper about phytoplasmas:
http://www.plantgem.unina.it/A...
It's a little technical, and a little sketchy. But it it makes some interesting points:
- Phytoplasmas are related to bacteria, have no cell walls, and, in fact possess a rather limited subset of the biochemical machinery that had, until their discovery, been assumed to be needed by all living organisms.
- This makes them utterly dependent upon their hosts. They cannot, for example, be cultured in a petri dish. And this is one of the reasons they have only recently been studied.
- They tend to travel lightly, change surface morphology fluidly, and live off the land, making it very difficult for the immune systems of their hosts hunt them down and destroy them.
- They have been implicated in a lot of plant diseases: the symptoms of which are frequently either "witches broom" formations or leaf yellowing. The consequences are generally destructive in cultivated plants, but there is an exception in poinsettias.
- Interestingly, phytoplasmas are sensitive to tetracycline.
- There is evidence to suggest that certain other microorganisms might aid plants in recovering from phytoplasma diseases.
...
One thing that occurred to me in reading this was that in the case of phytoplasmas it takes the carrier insect three weeks from the moment of ingestion to the moment it is infectious and can transmit the disease. If one had the technology and were inclined to do so, it might hypothetically be possible to clean the garden of insects every two weeks, meaning that each new infected insect would have to fly in from somewhere else. Not sure I'd be inclined to try to do this because if pesticides were used it could devastate the populations of insect predators, making the garden completely dependent on the gardener for insect control.
Another idea is to spray plants with lemon or eucalyptus oil or some other agent that repels insects.
