An entirely autonomous (i.e., self-organising) pathosystem in which people have not interfered, either directly or indirectly. It is characterised by its stability, by genetic diversity, and by genetic flexibility. It may be either continuous or discontinuous. A vertical subsystem can evolve only in a discontinuous wild pathosystem. Research into plant parasitism has been confined almost entirely to crop pathosystem^, and there is an urgent need for research into wild plant pathosystems. Wild progenitor
In crop science, the term 'progenitor' usually means the original wild ancestor. Every cultivated species of plant has one or more wild progenitors, some of which are extinct. Wilt disease
A plant disease in which the principle symptom is wilting, in spite of an adequate moisture in the soil. Wilts are usually caused by microscopic fungi such as Verticillium spp., or Fusarium spp., or by bacteria such as Pseudomonas spp. The wilting results from the fact that the water conducting vessels of the plant are occupied by the parasite, and are partly blocked. The parasite may also produce toxins that induce wilting. Wind-borne parasites
Any parasite that is dispersed by wind. Most fungi and many insects are wind-borne. Wind dispersal can carry parasites for hundreds of miles. There is even evidence of aphids being carried across oceans on the jet stream. Windbreak
A hedge or line of trees planted to protect crops from persistent winds.
Was this article helpful?