What are the protozoa causing diseases in plants?

One possibly unexpected group of plant pathogens is the Trypanosomatida—the same group that includes Leishmania and Trypanosoma, the causative agents of kala-azar, African sleeping sickness, etc. It also includes the genus Phytomonas, which live in phloem cells and latex vessels of various plants. read more

According to Ohio State University at Mansfield's Dr. Stephen Abedon, protozoa can perhaps be best defined for what they are not, rather than what they are. Protozoa are not animals, plants, algae, fungi or virus. They are, however, parasitic. As a result, these tiny organisms can cause a variety of diseases in humans, animals and plants. read more

So there don't seem to be many motile, heterotrophic, single celled "protozoa" that infect plants. In fact, these are the only ones I could find. Most of the protists that infect plants are superficially fungus-like and have traditionally not been called "protozoa". read more

Microbes or Microorganisms – Diseases Caused by Microorganisms – Diseases Caused By Bacteria, Viruses, Protozoans and Fungi. read more