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MOLD: A COMPLETE GUIDE to TEST CLEAN PREVENT
AIR CLEANER PURIFIER TYPES
AIR FILTERS for HVAC SYSTEMS
AIR POLLUTANTS, COMMON INDOOR
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ALLERGEN TESTS for BUILDINGS
ANIMAL ALLERGENS / PET DANDER
ANIMAL ODORS IN BUILDINGSS
ATTORNEYS and EXPERT WITNESSES
BIBLIOGAPHY ENVIRONMENTAL HEALTH, MOLD, IAQ
CAR MOLD CONTAMINATION
CARPET DUST IDENTIFICATION
CARPET MOLD CONTAMINATION
CAT DANDER in BUILDINGS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
CPSC Indoor Air Pollution Book Online Copy
DUCT SYSTEM & DUCT DEFECTS
EMERGENCY RESPONSE, IAQ, GAS, MOLD
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN BUILDINGS-mold
GAS EXPOSURE EFFECTS, TOXIC
HUMIDITY CONTROL & TARGETS INDOORS
HOUSE DUST ANALYSIS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
MILDEW REMOVAL & PREVENTION
MOISTURE CONTROL in BUILDINGS
MOLD GROWTH on SURFACES, TABLE OF
MYCOPHOBIA, STAINS MISTAKEN for MOLD
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURES
OZONE for MOLD OR ODORS
RADON HAZARD TESTS & MITIGATION
SAFETY HAZARDS GUIDE
SICK HOUSE IAQ QUESTIONNAIRE
SMELL PATCH TEST to Track Down Odors
STAIN DIAGNOSIS on BUILDING INTERIORS
VENTILATION in BUILDINGS
What's the difference between mold & mildew? This article explains the difference between mildew and mold (or other forms of mold). As we discuss in this article, mildew, a sub-class of molds, is an obligate parasite that grows only on living plants, and is generally white in appearance. Our page top photograph shows mildew growing on a jasmine plant at a Vassar College home in Poughkeepsie, New York. More photographs of mildew are included in this article. At Distinction between "mold" and "mildew" on books we discuss more aspects of the difference between mildew and other molds, and why that difference matters.
Also see MILDEW REMOVAL & PREVENTION (what to do about mildew), and see MILDEW ERRORS - MOLD PHOTOS (mold that might be mistakenly called mildew). Readers who need to cure or prevent efflorescence, mold or "mildew" in buildings should see STAIN DIAGNOSIS on BUILDING INTERIORS, and MOISTURE CONTROL in buildings as well as HUMIDITY LEVEL TARGET also VENTILATION in BUILDINGS and WATER ENTRY in buildings.
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Our closeup photographs above show powdery mildew growing on the leaves of a jasmine plant. Mildew is a specific type of mold that grows on living plants. Just on plants. Notice that this mold (mildew) is white? Mildew is always white or perhaps light gray in color.
Readers concerned with building mold contamination should see MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD. At this website, other photos of mold on indoor building surfaces may help you recognize mold in buildings, recognize probably-cosmetic mold, and recognize stuff that is not mold and does not need to be tested. See MOLD APPEARANCE - WHAT MOLD LOOKS LIKE for photographs that help recognize mold growth in buildings. See MOLD APPEARANCE - STUFF THAT IS NOT MOLD for other substances sometimes mistaken for mold in or on buildings. Also see Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens on indoor building surfaces.
See Mold Atlas & Particles List for an atlas of building molds and for more microphotographs of building mold samples observed in our laboratory see MOLD by MICROSCOPE. Our Atlas of Mold Related Illness Symptoms & Complaints provides details about specific mold genera/species and their health effects.
What Does Mildew Look Like
Though both of these groups may also include other species, they all look similar on plants - white or gray powdery or splotchy deposits on plant leaves and stems. Mildew may appear on the plant's buds, flowers, fruits, in sum, just about on any live plant tissue, though not so likely on heavy dry bark such as on tree bark or on woody stems. See our plant photographs earlier in this article.
Our lab microphotograph (above-left) shows the hyaline (colorless) spores of Oidium-Erysiphe that we collected from the jasmine plant shown in the photographs in this article. In the microscope, mildew spores (Oidium-Erysiphe) are colorless; on a plant this mold species appears as a white powdery substance.
In sum, mildew is a white powdery fungus that is an obligate parasite found on living plants.
No. Mildew grows on living plants.
But lots of people (incorrectly) call various building molds "mildew", and lots of mold cleanup products use the words mildew or mildewcide in their name and instructions.
In a practical sense, making the mistake of calling an indoor or outdoor mold found on a building "mildew" is not a big deal. With the exception of avoiding spending on costly cleanup of harmless cosmetic molds or stains, the mold remediation and mold prevention procedures in a building are about the same regardless of mistakes in naming the mold.
You won't find mildew on or in a building on anything but a living plant, despite the names found on indoor or outdoor cleaning products that use the term "mildewcide" and "mildew-resistant product", or found in "mold reports" or in home inspections notwithstanding.
We think that mildew just a less scary name that some folks like to use to describe mold found in buildings, especially in real estate sales. We think that mildew is used on mold cleanup products or mold-resistant products also because of the widespread use of that word by consumers faced with an indoor mold problem.
What Does it Mean if Your Inspector or Mold Expert Calls it Mildew?
See MOLD EXPERT, WHEN TO HIRE for help in deciding if you need a mold expert or not. But if your "mold expert" or home inspector tells you that s/he found mildew growing in or on the building, that person may be less of an expert on finding, identifying, and removing problem mold than you hoped, and therefore
At Distinction between "mold" and "mildew" on books we discuss more aspects why the difference between mold and mildew matters.
If your "mildew" is found on building surfaces, it is mold, but it is not mildew, and you need to follow normal mold cleanup procedures. See BASICS YOU NEED to FIND, TEST, REMOVE MOLD for a detailed step by step guide to removing problem mold and for identifying and fixing the cause of mold growth in the first place.
If you are having trouble tracking down a moldy smell in your building, try the suggestions we describe at ODORS & SMELLS DIAGNOSIS & CURE.
If your mildew is indeed growing on a living plant (tomatoes, grapes, crops, house plants, other plants) it can weaken or even kill the plant, at least by interfering with photosynthesis. Mildews on plants may be a species of mildew fungus that is plant specific. For example a mildew that grows on grapes may affect only those plants and may not infect nearby plants of other types, roses for example. But the conditions that cause powdery mildew to grow on plants invite infection of many plants in a given area. These include crowding (poor air circulation within or around the plant), and dampness or high humidity. If a plant is already stressed or weak from other conditions, it may be more susceptible to mildew infection as well.
While lots of "mildew cleaning" products are sold with the intention of removing mold from building surfaces (bathtub tile grout, for example), do not use such products on plants - you will probably kill the plant.
See MILDEW REMOVAL & PREVENTION for details on what to do about cleaning off or removing mildew, and how to both cure and prevent mildew.
Mold on or In buildings - Molds that are Mistaken for Mildew
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