I love growing tomatoes; I can use them in salads, soups, and so much more. I even use the leaves to not waste them, and they are tasty.
When I spotted what looked like a white powder on my tomato leaves, I was very worried.
How do I treat this? Is this preventable for next time? And can I still use my tomatoes at least?
I really didn’t want to say goodbye to all of my tomato crop.
White Powder on Tomato Leaves
The white powder on tomato leaves is powdery mildew that looks like a thin layer of white or light gray talcum powder. It’s a fungal disease that develops on the leaves when the tomato plant doesn’t receive enough sunlight, when the humidity is too high, and when air circulation is poor.
What Causes White Powder to Form on Tomato Leaves
When I first found the white powder that looks like talcum powder on my tomato leaves, my sister who is very knowledgeable about plant diseases and fungi shared that this is powdery mildew, which is caused by a fungal disease.
The fungi thrive in stagnant, moist, and dark areas. This disease generally takes root when the humidity levels are 70% and higher and when the plant doesn’t receive enough sunlight or air circulation.
All of these conditions provide the fungus with the right environment to reproduce and grow, and as a result, white spots or powder appear on the tomato plant’s leaves.
Powdery mildew is more common in young tomato plants since avid gardeners tend to over-fertilize to help improve the tomato yield.
However, with a boost in nutrients from the fertilizer, the plants grow at a faster rate and the new leaves that are sprouting and growing are a good place for the white powder fungus to grow.
Steps to Rid of Powdery Mildew on Tomato Leaves
The best way to get rid of powdery mildew, as I’ve learned, is to tackle it as soon as you spot it.
Let’s look at the steps I followed to get rid of this fungus disease:
Step 1: Prune the Infected Leaves
The first step I take when I spot powdery mildew on the leaves of my tomato plants is to prune the infected leaves with sanitized pruners or garden shears.
This helps prevent the white powder from spreading further and it also helps improve the air circulation around the plant.
If all or a lot of the leaves are infected, I take care to only remove the ones that look most infected. Removing all or too many of the leaves can kill my tomato plant or put it in shock.
Once I’m finished pruning, I sanitize my equipment again to ensure it doesn’t spread when I use my pruning shears the next time.
Step 2: Spray a Fungicide
After pruning, I use an organic fungicide to get rid of the powdery mildew on the leaves. I’ve found that neem oil works wonders.
I generally spray neem oil on the leaves about once a week until I see the fungus has died and stopped spreading.
The other option for a fungicide is to use milk spray, where you can combine 3 parts water with 2 parts milk. Also, spray this on any infected leaves once weekly.
A third option is to mix a solution of 1 tablespoon of baking soda, 1 tablespoon of light vegetable oil, 1 tablespoon of non-detergent liquid dish soap, and 1 gallon of water.
This solution works best when I see the white powder first appearing on the leaves as it stops the progression of the fungus disease by changing the pH from acidic to alkaline.
I also thoroughly coat the leaves in this solution and then apply it weekly.
If it has rained after I’ve sprayed my fungicide, I reapply the organic fungicide.
How to Prevent White Powder on Your Tomato Leaves
I’ve found that the best way to treat powdery mildew on my tomato leaves is to actually prevent this fungus from growing and spreading in the first place.
So after my first run-in with the white powder on my plant’s leaves, I’ve probably taken prevention to the next level.
Just how do you prevent powdery mildew on your tomato plants?
I’ve made sure that my tomato plants get direct sunlight for at least 6-8 hours a day and are planted so that they get adequate air circulation.
I generally plant my tomatoes 18-24 inches apart from each other so the area where these plants are planted doesn’t become overcrowded, thus air circulation is improved.
I also prune the leaves now and again if the plants grow too bushy.
I only feed them a low-nitrogen fertilizer that releases slowly at planting time.
The other prevention method is to plant varieties of tomatoes that are more resistant to powdery mildew. I really love Granadero, and since my garden has a history with this white power on tomato leaves, I plant quite a lot of this tomato variety.
Frequently Asked Questions about White Powder on Tomato Leaves
What is the white powdery stuff on my tomato leaves?
The white powdery stuff on your tomato leaves is a fungus disease that is commonly known as powdery mildew among gardeners. It infects your plant’s leaves when the humidity levels are high, your plants are growing in a dark and damp area devoid of direct sunlight, and there is a lack of air circulating around your tomato plants.
Can you eat tomatoes with powdery mildew?
Technically, you can eat the tomatoes if they are healthy-looking even if the leaves are infected with powdery mildew. If you don’t get the white powder on the leaves under control, the fungus disease does weaken the plant, affect the taste of the tomato fruits, and negatively affect the yield.
The Final Word
Prevention is always better than cure, and this is true when you find white powder on the leaves of your tomato plants.
This powdery mildew is caused by a fungus, and while you can still eat healthy tomatoes, you should eliminate the fungus by pruning infected leaves and/or spraying the leaves with an organic fungicide, like milk spray or neem oil.
To prevent the white powdery fungus from setting up camp on your leaves, ensure your tomato plants get 6-8 hours of direct sunlight a day, there is enough space around each plant for air to circulate, and don’t over-fertilize.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.