What Is The Best Powdery Mildew Treatment to Use?

The best powdery mildew treatment is Bonide BND1428. However there are other’s that we have covered here for you to consider and give you options.

There is nothing more dejecting than watching your lovely, healthy-looking herbs and veggies get attacked by pests or disease.

Powdery mildew is one of the most common diseases that afflict the home garden, especially if yours has been around for a while. Caused by many different types of fungus, you’ll find white, powder-like spots on the leaves and stems of your plants.

If you don’t do something about the problem, it can quickly spread, hampering your plants’ vegetative growth and ability to flower and fruit.

Thankfully, there are several powdery mildew treatments available for this. If you want to grab something and spray your garden real quick, check out our top recommendations.

Our Top 4 Powdery Mildew Treatments


Let’s take a closer look at our recommended mildew treatments now. We’ll go over mostly organic solutions that will get rid of mildew and insects easily and fast.


Bonide (BND1428) - Sulfur Plant Fungicide, Organically Controls Rust, Leaf Spot and Powdery Mildew (4 lb.)

Key Features:
  • 100% organic, so you won’t be eating anything questionable in your veggies later on
  • It is broad-spectrum and will work on more than just powdery mildew. Sulfur works on a multitude of fungal diseases and is also an effective insecticide. Two for the price of one.
  • Helps plants with magnesium uptake
  • Can be applied once in two weeks, or weekly if the powdery mildew is widespread

This sulfur-based spray from Bonide is a safe, organic option that can be applied to any garden area affected by powdery mildew.

Whether you have precious, precocious roses, veggies, or fruits, sulfur is one element that is safe to use on all plants. Unlike some other compounds like lime, sulfur doesn’t burn the foliage on your plants.

Bonide is one of the best-known brands in the gardening industry, trusted by millions of home gardeners. They have a reputation for producing quality, yet affordable chemicals for the garden.

2. BONIDE Copper Fungicide

Bonide 811 Copper 4E Fungicide 16oz (473ML)

Key Features:
  • 100% organic and safe to use. Just follow the package instructions to work out the correct dosage.
  • A broad-spectrum fungicide that works on powdery mildew, but also other diseases like rust and blackspot.
  • Can be dusted onto plant leaves as a powder or mixed with water and sprayed on using a hosepipe or tank pump.
  • Easy to mix and apply

This is another product from the popular and reliable Bonide brand. Copper has been used even by commercial farms to control not only powdery mildew but a whole range of plant diseases.

Easy to use, this product is also 100% organic. This means you get the benefits of disease control without potentially poisoning your plants or yourself when you eat your home-grown fruit and veggies.

This product can be applied as a spray, or mixed with water and sprayed on using a hosepipe or tank sprayer. Copper helps control both powdery and downy mildew, as well as blackspot, rust, and many other fungal diseases.

3. BONIDE Neem Oil

Bonide (BND022 - Ready to Use Neem Oil, Insect Pesticide for Organic Gardening (32 oz.) - 2 Pack

Key Features:
  • 100% organic, safe to use on any kind of plant
  • Works as both fungicide and very effective insecticide
  • Remains on plant leaves as a protective coating
  • The bottle comes premixed, just apply where needed
  • Best for prevention of powdery mildew

Neem oil is extracted from vegetative parts of the Neem tree. In India, its native country, this oil has been used for centuries as an anti-fungal and anti-inflammatory.

This oil may not be as effective as sulfur or copper at dealing with an existing powdery mildew infection, but it’s great at the preventive stages. This particular bottle from Bonide comes ready to use, so no need to premix anything.

Neem oil is also an effective insecticide and works against bugs at all stages of the development cycle. It also remains as a dormant coating on your plant leaves, helping protect them throughout the various seasons.

4. Spectracide Multi-Purpose Spray

Spectracide 100507462 Immunox Multi Purpose Fungicide Spray Concentrate, 16 fl oz

Key Features:
  • Not organic
  • Active ingredient Myclobutanil
  • Broad-spectrum, covers a lot of diseases, not just powdery mildew
  • Easy to mix and use, dosage details are provided on the product label
  • Extremely effective
  • The product comes with a 100% money-back guarantee as proof of quality and efficiency

Sometimes, no matter how diligently you maintain your garden in tip-top shape, diseases and pests will still attack. And often, the first and most popular treatments you try may become less efficient over time.

If this happens, you’ll be spraying religiously and keeping the growing conditions just right, but your plants will still suffer from powdery mildew and other diseases.

Their multi-purpose spray from Spectracide uses Myclobutanil as the active ingredient. The spray is designed to be rain-resistant too, so it will remain on the plant, helping prevent any further attacks.

The biggest downside here is that it is not organic. If you intend to eat your fruit or veggies, be sure to follow the manufacturer’s instructions and wait the required number of days after spraying before harvesting your produce.

Exactly What is Powdery Mildew?

When someone talks about powdery mildew, they could be referring to any of a large number of different fungal plant diseases.

But all these fungi tend to act in a similar way. They will start on one spot on a leaf or stem and gradually spread to cover the entire vegetative part of the plant.

Once this happens, the affected plant will not be able to carry out photosynthesis and utilize its nutrients anymore.

If you don’t catch it early and do something about it, the plant may be damaged so badly that you’ll just have to uproot and get rid of it.

Signs and Symptoms of Powdery Mildew

When it first affects a plant, it will usually appear as a small, white spot on a leaf somewhere. The spot will grow bigger as the disease progresses, looking like white, powdery dust.

The fungal infection can quickly spread from just one leaf to the entire plant, covering all the leaves, and even the stems. And from there it’s just a short step to infecting other, healthy plants until your whole garden is affected.

Not to be Confused with Downy Mildew!

Powdery mildew is often confused with its cousin, downy mildew. The two diseases are similar, but it’s not too hard to tell them apart.

First, look at where on the plant the infected spot has appeared. Downy mildew grows only the underside of leaves, while powdery mildew will grow anywhere.

Second, downy mildew spots don’t have the distinct white powder. So if your plant just has leafs full of yellow spots on the underside of the leaves and no powder, then it’s downy mildew you’re dealing with.

How to Prevent Powdery Mildew from Attacking Your Garden

As the saying goes, prevention is better than cure. Unfortunately, fungal spores are often carried around by the wind. Whenever they land on a leaf and the conditions are right, they waste no time multiplying.

So total prevention may not be possible. But taking the best possible care can save you large losses, helping prevent any infection from turning into an outbreak.

Powdery mildew is rarely a problem in moist conditions, but there are plenty of other diseases that like it wet and humid, so that is not a solution.

But much as you cannot completely prevent powdery mildew from attacking your garden, there are a few things you can do to help the situation:

  • Begin by choosing veggie and herb varieties that are resistant to powdery mildew
  • If you do have some varieties that are prone to this fungus, make sure not to plant them in the shade.
  • Spray your garden on a regular basis to keep all plant leaves moist.
  • Manage aphids and other pests, as they can carry the spores into your garden from elsewhere.
  • If you do find a sick leaf or stem, remove it immediately to prevent the disease from spreading any further.
  • In a case where the whole plant is covered in powdery mildew, dispose of the entire plant, no matter how valuable it was to you.
  • If you have a serious mildew problem, there is a variety of professional treatments to manage the situation.

How to Treat Powdery Mildew

Once powdery mildew has invaded your garden, it can be really hard to permanently get rid of the problem. You’re likely to keep on facing outbreaks as the weather changes and the conditions for the fungus become more favorable.

The only solution is to manage the problem by using one, or even a combination, of professional treatments regularly. There are some simple home remedies too, but they may not be as effective.

Neem Oil

Neem oil is extracted from the fruit and seed of the Neem tree. Native to India, it can now be found in other tropical parts of the world too.

This tree has been revered for centuries as a medicinal plant. It has been used to treat malaria and inflammation and is known to be anti-fungal, and an effective insecticide.

Thanks to globalization, it is possible to buy Neem oil sprays for your garden, no matter where you are.

Neem oil is very effective as a preventative but may not work as well if powdery mildew is already well-established in your garden.

Sulfur-based Sprays

Sulfur is an element that has been used for centuries to treat all sorts of fungal infections in people and animals too, not just plants.

Sulfur-based sprays are easy to get hold of. All gardening stores and supply centers will have them. Sometimes, even larger supermarkets will carry them, especially during the spring and summer months.

Copper-based Sprays

Copper sulfate is another common ingredient in commercial fungicides. It has been used as a fungicide for decades, even in larger commercial farms.

Copper-based sprays are readily available. Just visit your nearest garden center or buy one online.

Sulfur and Lime Sprays

Sulfur on its own is an effective control mechanism for powdery mildew and other fungal infections, but adding lime seems to make for an even more effective mixture.

Just be careful as spraying with a high concentration or too frequently can burn the foliage of your plants. If you opt for one of these, be sure to follow instructions to the tee.

Homemade Remedies

There are some simple home remedies available, based on everyday ingredients you probably have in your kitchen.

Baking soda, milk, household vinegar, wood ash, and ethanol-based mouthwashes have all been used to treat powdery mildew and other fungal infections in gardens.

How effective these remedies remain questionable, as gardeners usually still end up going for a commercially available spray.

But one idea that might make sense is to use a mixture of two or three methods to handle powdery mildew and prevent a fresh outbreak.

You could combine spraying with a sulfur- or copper-based spray one week with using natural Neem oil or a homemade remedy like milk or baking soda the next.


Powdery mildew is not necessarily fatal to a plant, but it can cause a lot of damage. It’s not just about your plant looking ugly: vegetative growth will suffer, and you may not get the bumper harvest you hoped for.

Getting rid of this disease can be really hard once it has set in, so the best approach is to prevent it before it ever happens.

By planting powdery mildew resistant varieties and doing some preventive spraying, it is possible to keep your garden free of mildew.

There are some home remedies available, but for the most efficient results, you’ll probably need a commercial sulfur- or copper-based spray. Take a look at our top 4 for some of the best powdery mildew sprays around.

You can alternate different treatments for better results, using a commercial spray one week, and something like Neem oil or a home remedy the next.

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