Mold under a Microscope

What does mold under a microscope look like?

Here’s a quick tip: Mold under a microscope looks like regular, smooth shapes – spheres, grapes, clubs, elongated soccer balls, and so on. Mold does not look like irregular, jagged particulates. You will see a lot of dust and debris under the microscope. Look for the smooth shapes.

Here’s another tip. There are thousands upon thousands of types of fungi (which is another generic name for mold). Happily, only a half dozen – or maybe a dozen – genera¬†are commonly found in homes.

“Genera” is the plural for “genus.” Remember “genus” and “species” from your high school biology? For example, if you have Aspergillus niger in your home, Aspergillus is the genus, and “niger” is one of about 200 species of Aspergillus.

Thus, you don’t have to feel overwhelmed, that you’d never remember all the types of mold that might be visible under the microscope. There are only a relatively few genera that would typically show up in a tape sample from your home.

Here are 8 common fungi in homes:

  • Alternaria
  • Aspergillus (pronounced as-per-jill-us)
  • Chaetomium
  • Cladosporium
  • Penicillium
  • Stachybotrys
  • Trichoderma
  • Ulocladium
¬†Now I’ll lead you through a tour of mold under a microscope, concentrating on these 8 genera.
Alternaria growth
Alternaria growth

Alternaria is a common outdoor and indoor mold. Spores are large, and growth is darkish. It grows in leak areas, such as under a shower pan. One young fellow said his asthma worsened as soon as he climbed the steps to the 2nd floor of his home. The culprit was a tiled shower with an improperly sealed ledge. Water seeped under the shower pan and under the common wall with the chap’s closet.

Immature Aspergillus fruiting body
Immature Aspergillus fruiting body

to be continued….




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