We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is an Oidium?

By Ray Hawk
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Oidium is variously referred to as a fungal spore, which is the offspring body of a fungus, or as an actual fungi itself of the Ascomycota order. It is more commonly known as powdery mildew due to its parasitic nature of existing as a soft film on the surface of host plants such as grape vines. Mildew odium can have a devastating effect on wine crops, and is known to have contributed to the near collapse of the wine industry in Europe in the mid-19th century.

Within the Ascomycota order for fungi, there are a great variety of forms, but they share the common feature of being spore shooters that distribute their offspring by rapidly dispersing them into the surrounding air. The Oidium group is a subdivision within this order known as a genus that contains dozens of species. Almost all Oidium species are known to be plant pathogens that exist and act as powdery mildew agents on the surface of the green parts of vines. They attack the vines and turn them black, as well as yellowing foliage in the process, causing the plants to wilt. While an Oidium fungus does not always kill the host plant, it will reduce its growth rate and, in the case of grape vines, affect the skin color of grapes, which ultimately degrades the final wine product produced from them.

Fungi have a propensity to spread quickly in damp, cool environments once established, such as in vineyards, but the cause of the ongoing wine crop devastation in Europe in the 19th century was partially manmade. A worldwide scientific interest in botanical specimens led European horticulturalists to import wild vine samples from the US for study. At the same time, Henri Marès, a Frenchman, had perfected a method of sulfuring vines to protect them from Oidium infections. The American vines carried Oidium, as well as an infestation of tiny yellow-green aphids of the genus Phylloxera, to which they were naturally resistant. The European vines had no resistance to the aphids and they rapidly spread throughout European vineyards over the next 11 years, causing additional crop loss from plants that had not already succumbed to Oidium.

From 1854 to the 1880s, vines died off across a broad region of western Europe centered on France, primarily from Oidium and Phylloxera attacks, as well as from downy mildew and black rot which also were carried in on imported species. It wasn't until European vines were grafted into American strains to build in resistance to these pests at the end of the 19th century that the crops began to recover. Other species of Oidium still present problems with crop growth as of 2011. These include the Oidium lycopersicum species that attacks tomato vines and is found throughout the US state of Connecticut, and the Oidium mangiferae species that attacks mango trees in the Far East countries of China, India, and Pakistan, as well as other regions of the globe such as Mexico.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Link to Sources
Discussion Comments
By anon1000143 — On Jun 09, 2018

Does water mold show up on a mold test? Does water mold have mycotoxin? Can humans become infested with water mold?

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.