Mold and mildew are types of fungi; typically, mold is black or green, and mildew is gray or white. Mold tends to grows on food, whereas mildew is an issue on damp surfaces, like bathroom walls, basement walls, or fabrics. Mold grows in the form of multicellular filaments or hyphae, while mildew has flat growth. Mildew is often referred to as a kind of mold (or mold in its early stages), and is classified as powdery (under the order Erysiphales) and downy (under the family Peronosporaceae).
edit Differences in appearance
Mold has a fuzzy appearance and can be an orange, green, black, brown, pink or purple in color. Downy mildew starts as yellow spots that first become brighter in appearance and then the color changes to brown. Powdery mildew is whitish in color and looks like talcum powder. These white spots slowly turn yellowish brown and then black.
edit Health Effects of Mold vs Mildew
Prolonged exposure to mold spores can cause health problems such as allergic reactions and respiratory problems, due to the toxins (mycotoxins) it produces.
Mildew can cause damage to crops and other plants it infests. Inhalation of mildew can cause coughing, headache, scratchy throat and lung problems. Mildew can also start growing in lungs and cause other serious health problems.
edit Toxic vs. Allergenic Mold
This video explains the difference between toxic and allergenic mold (mildew).
edit Prevention and Control
To prevent mold and mildew in your home, you need to keep all the areas dry and moisture-free. Check the humidity levels inside the house and take measures to control it. Fix any leak in the bathroom, kitchen or other areas. Have your heating and cooling systems regularly inspected. Finish perishable food within 3-4 days.
To protect crops from mildew use seeds that are resistant to mildew, remove infested plants and weeds; avoid overhead heating, plant crops that are resistant and susceptible to mildew in rotation to prevent the growth of these fungi.
edit Biological Differences
Molds obtain their energy from food and other organic matter. Enzymes secreted from the hyphae breakdown complex molecules such as starch, cellulose and lignin into simpler substances, and then absorbed by the hyphae. Reproduction may be sexual or asexual through spores. These spores are airborne and able to survive in extreme conditions. Mold has a musty smell and is only visible to the naked eye when the colonies start growing.
Mildew is found on host plants like beans, maize, potato, tomato, rice and other plants. Mildew also grows on clothing, leather, paper, shower curtains, window sills where the moisture content is high. Reproduction is both sexually and asexually, via the production of spores.
Some of the common mold genera include Acremonium, Aspergillus, and Penicillium, the latter of which includes a species (Penicillium chrysogenum) used in penicillin antibiotics. Examples of mildew include Peronospora sp, Blumeria, and Podosphaera.
Some molds are used in food production. For example, Penicillium is used in the production of cheese, Neurospora in the production of oncom, which is made from the by-product of tofu, other molds in the production of bread, soya sauce and so on. Mildew has no uses as such in food production.