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Powdery Mildew Fungi: Classification and Ecology

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Powdery Mildew Fungi: Classification and Ecology

In this laboratory exercise, learners will discover how many different plant hosts they can find that are infected by the same genus of a powdery mildew fungus, or how many different genera of powdery mildew fungi can be found on the same plant host. This exercise demonstrates the diversity that exists within a fungal order. With a good collection of leaves infected with different powdery mildew fungi (collected by learners or instructor), learners use a written key and/or an illustrated key (or could even make their own key) to identify the powdery mildew fungus to genus. Since powdery mildew fungi reproduce by means of two spore types, asexual spores (conidia) and sexual spores (ascospores), discussions of the types of reproduction in fungi can be facilitated. Note: This lab works best in regions that experience cold weather for part of the year, since this encourages production of cleistothecia (sexual stage). Please scroll down for activity component links.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
45 to 60 minutes

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 11 - 18

Resource Types:
Activity, Experiment/Lab Activity, Lesson/Lesson Plan


Materials List (per group of students)

  • Newspapers, old telephone books
  • Plant press, heavy books, or large catalogues
  • Manila envelopes
  • Paper for collection labels
  • Fresh or dried plant leaves with powdery mildew and mature (black to the naked eye) cleistothecia
  • Water in dropper bottles
  • Binocular dissecting microscopes
  • Compound microscopes
  • Dissecting needles or toothpicks
  • Pencils with good erasers
  • Micropipettes or Pasteur pipets and bulbs (optional)
  • Microscope slides and cover slips
  • Transparent tape
  • Hot plate (optional but helpful)
  • Large 800 ml beaker or coffee can (optional but helpful)
  • Piece of screen to fit in the beaker (optional but helpful)
  • Tong or forceps (optional but helpful)
  • Envelopes (optional but helpful)


  • Life Sciences
    • Diversity of Life
      • Plants
      • Protists and Fungi
      • Classification
      • Biodiversity
    • Ecology
      • Biodiversity
    • Evolution
      • Evidence for Evolution
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations
      • Communicating Results

Informal Categories

  • Gardening
  • Nature and Environment
  • Outdoor Activity


To use this activity, learners need to:

  • see
  • see color
  • read
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access


  • Ruhl, Gail E.; Jasalavich, Claudia A.


  • All Rights Reserved, The American Phytopathological Society, ©2011