Indeed, mycology, the scientific study of fungi, is still done today in botany departments. However, in modern biology, fungi are not considered plants. A good example is the growth of the target spot fungus on this ripe tomato fruit. Target spot on ripe tomato fruit. Most of the time, however, careful examination with a microscope is needed to see fungi and ultimately identify them.
Fungi consist of multi-celled microscopic strands.
Often, spores, or the reproductive structures of fungi are readily visible, as seen in this photomicrograph of the fungus Botrytis . It is the peculiar size, shape, coloration, etc. of these spores that are most useful in identification of fungi, including those that cause plant disease. Sometimes, we encounter important pathogenic fungi that do not readily form spores. A good example is the root-infecting fungus, Rhizoctonia , shown here. Our next group of pathogens is the bacteria .