Last Updated on January 18, 2023 by Grow with Bovees
Have you ever noticed those white powdery spots, or a coating on leaves on your plant?
Well, that’s a common fungus called powdery mildew.
It is a common problem in gardens, and infects a wide variety of plants. Most commonly, cucumbers, melons, roses, tomatoes, eggplants, lima beans and pea plants.
But is powdery mildew harmful to humans?
The short answer is yes and no, because these fungal spores don’t pose a direct threat to humans, but can be indirectly harmful.
What is Powdery Mildew?
Powdery mildew is a fungal disease that, apart from plants, can be found anywhere, especially in areas that have high relative humidity at night, low relative humidity during the day, and temperatures of 70° — 80° F.
This white mold can be identified easily by its dusty splotches of white or grey powder laying across the top of the infected leaves of your plants.
If left unattended, powdery mildew can spread quickly and cover your plant’s leaves, making it look as though they’ve been sprinkled with flour.
Powdery mildew spores can drift into your home, and quickly spread, affecting your indoor houseplants.
How is White Powdery Mildew Harmful to Humans?
Powdery mildew has an unsightly appearance, and though several infestations can damage your plants, it won’t harm you if you don’t touch it, so avoid leaf contact.
It is important to control powdery mildew in your home, because even though this fungus isn’t directly harmful to humans, it can harm potential food sources.
For example, if powdery mildew affects your fruit and vegetable plants, the infected plants will not produce fruit or will produce fruits and vegetables that have an inferior taste. Severe infections have been known to cause the death of plants.
Adding to this, exposure to a high number of powdery mildew spores can make you allergic or intolerant, and can trigger a wide range of health problems, including respiratory problems and eye irritation.
If you or your family members suffer from allergic reactions or asthma, exposure to powdery mildew can irritate the eyes, nose, throat, and/or lungs.
Given the above reasons, it is best to control powdery mildew in your home, as soon as you see the smallest traces of white mold.
How to Control Powdery Mildew?
Once your plants are heavily infected with powdery mildew, it is difficult to get rid of this persistent fungus. The first thing to do is remove all the infected stems, leaves and fruit, and destroy them either by burning them or throwing them in the trash.
Do not add the items infected by powdery mildew to your compost pile, as powdery mildew diseases can spread easily by the wind, and remain in the compost materials.
If you use tools such as scissors or pruners to prune the infested plants, sterilize these tools with rubbing alcohol before using them on your healthy houseplants.
Homemade Solution for Killing Powdery Mildew Spores?
There are several effective fungicides available to kill powdery mildew such as neem oil, sulfur, and potassium bicarbonate.
However, these fungicides to treat powdery mildew are, in most cases, only effective when used prior to the infection or during the initial stage of the powdery mildew infection.
Many gardeners claim that baking soda is also a very effective way to treat powdery mildew. Simply mix a teaspoon of baking soda with one cup of water, and spray the plants generously. This solution will only kill the fungal diseases it comes in contact with, so if it has infected your entire crop, be sure to cover the entire garden with your baking soda mixture.
Milk spray, believe it or not, is also highly effective at killing powdery mildew spores. Dilute the milk with water in a 1:10 ratio, and spray on your affected plants.
Common apple cider vinegar mixed with water is another homemade remedy option with which to spray your delicate flowers, and if you want to keep on the organic route, you can always elect to use organic apple cider vinegar.
You can even use these aforementioned solutions to prevent white powdery mold from infecting your plants.
The benefit of using these are that, unlike most commercial fungicide options, they don’t contain toxic chemicals, so will not have bad effects on the quality of vegetable that you eventually harvest.
Apply a Fungicide to Leaves with Powdery Mildew
When choosing a fungicide to spray on your powdery mildew infected plants, look for one that contains neem oil, potassium bicarbonate, sulfur, or copper.
Mix one tablespoon of the fungicide, and 1/2 teaspoon liquid soap (not detergent) with one gallon of water, and spray liberally over the mild and severe infestations of powdery mildew.
How to Prevent Powdery Mildew?
They say prevention is better than cure, and this saying holds true for powdery mildew. The good news is that there are several ways to prevent powdery mildew including:
Planting powdery mildew resistant varieties
If you’ve had a powdery mildew infection in the past, planting disease-resistant plants in your garden can prevent the onset of powdery mildew. These plants include David garden phlox, jasper cherry tomato, and pink knock out.
Practice good growing techniques
Whether you have a powdery mildew problem or not, you should always employ good growing techniques to keep your plants healthy, so that they can ward off fungal problems.
Some of these practices include:
- Avoiding excess fertilization
- Providing full sun for most plants
- Keeping gardens well weeded
- Removing powdery mildew infected prunings from the yard
- Providing good spacing between plants
Use Compost Tea To Stop Powdery Mildew
Many growers use compost tea to prevent white powdery mildew. Compost tea infuses beneficial microbes such as rhizospheres into plants.
Some benefits of using this concoction for most powdery mildew infections include it can be made organically, and you can make your own.
But on the flipside, it takes a long time to brew an effective compost brew, and, needless to say, the unpleasant odor of compost tea.
To make your own tea, fill a bucket halfway with compost, and fill the remainder with unchlorinated water.
Let this mixture rest for about three to four days, and stir it occasionally. After three to four days has passed, string the mixture into another bucket, add more unchlorinated water to dilute the liquid, and mix this liquid with loose compost.
Powdery mildew can be harmful to humans, and certain species of plants, so it’s best to get rid of it from the get-go. It can especially harm people suffering from allergic reactions or those with respiratory infections in your home.
There are several ways to remove powdery mildew and prevent a mild and severe infestation of this fungal disease including making a homemade solution or with a fungicide.