White Spots On Basil Leaves (Why It Happens & What To Do)

Do you have white spots on your basil leaves?

You’re probably thinking, oh no, what the heck is wrong with my basil plant, or what is this wicked white stuff?

Today, we are going to help you with those white smudges on your basil leaves. We will tell you what it probably is, other issues that could infect your plants, and what you can do about it.

What Causes White Spots On Basil Leaves?

What causes white marks on basil leaves?

Several issues can cause white blemishes on basil leaves and stems.

Let’s look at a few of the culprits behind white stains on your basil.

Insects That Cause White Spots

Thrips

Thrips are tiny insects found on basil whose bodies are the shape and size of a comma. Thrips are generally found on basil leaves and not the stems. They survive by folding the leaf over themselves as a form of protection from other predators.

Mites

You can tell if you have mites or not as they will leave a white webbing underneath your basil leaves. Getting rid of mites can be done by introducing ladybugs or by using neem oil. The best way to detect and prevent these mites is to take a damp cloth and wipe down the leaves once a week.

Aphids

Aphid young who are generally white will gather in clusters. And fortunately, there are a couple of all-natural things you can do to help prevent or rid your basil plants of Aphids. One is to purchase some ladybugs. The other is to plant Nasturtium in your garden. Nasturtium not only provides a splash of color but Aphids absolutely love them so they will go after the flowers and leave your basil plants.

Adult aphids are even easier to remove. They come in red, yellow, brown, green and black, and in every case all you have to do is hose your plants down with water to remove them.

Whiteflies

If your basil is being damaged by whiteflies, they’ll gather around the leaves only to fly up off the plant when they’re disturbed. You can get rid of whiteflies by spraying your plants with an insecticidal soap (including the undersides of the leaves) in the evening when the heat of the day is not as bad. You can also use other insects like ladybugs.

Mealy Bugs

Mealybugs are white cottony insects that collect on both the leaves and stem of the plant. If you want to get rid of mealy bugs you can mix the following: 1 cup of Isopropyl alcohol, a couple of drops of Dawn dish detergent, and 1 quart of water in a spray bottle. Spray your plants and the dirt or mulch around them even the areas where you don’t see any mealy bugs. Repeat this treatment a couple of times a week until they are gone. If they reappear in a short time repeat the process.

Fortunately, all these pests can be treated with insecticidal soap. However, follow the directions and do not apply this if the plant needs water or during the heat of the day. Wait for sunset then spay the plants. Just be sure to wash them before you eat them.

Slugs

Slugs will also eat any tender vegetation in their path. Unfortunately, they are drawn to areas with high moisture such as under planters, mulch, boards, or rocks. However, luckily, there are a couple of ways you can get rid of slugs.

One is to encourage their natural predators such as toads, ducks, or chickens. You can also bait them with a melon rind turned upside down or a small snack pie pan with beer in it. Using the melon rind you can just pick it up in the morning with the slugs in it, then all you have to do is throw it away.

If you’re tryign the beer method, then the beer will drown the slugs.

You can also prevent slugs from getting to your plants by adding crushed eggshells or copper wire around the plants. Both eggshells and copper wire form a barrier that slugs will not cross.

Fungus That Can Cause White Spots

White Fungus

If your basil is suffering from white fungus you’ll notice white marks on the leaves. It most often happens when weather conditions are wet and damp frequently or for an extended period. To remove the fungus you’ll need to take off the infected leaves, ensure that the plants are getting plenty of sunlight and airflow, and use baking soda and potassium bicarbonate or all-natural fungicide to the plants according to directions on the package.

Powdery Mildew

Powdery mildew is another culprit which can cause white specks on your basil leaves. It generally develops during hot and moist or chilly weather. There are several ways to fix powdery mildew. One way is with Neem oil which can be applied in the evening so that any excess will not harm the plant in the sunshine. Another way is insecticidal soap using baking soda and potassium bicarbonate mixed with vegetable oil and soapy water.

Fusarium Wilt

Fusarium Wilt is also caused by fungus. The fungus is carried either by the dirt the plants are in or by the seeds of an infected plant. The symptoms include underdeveloped growth, drooping or yellowing leaves, brown spots or streaks on the stalk, stalks that are twisted, and leaves that drop off.

Unfortunately, there is no cure for fusarium wilt; you have to destroy the plant. And even after destroying the plant, you shouldn’t sow any basil or mint family plants in the soil for three years. 

Bacterial Leafspot

Bacterial leaf spot caused by the Pseudomonas cichorii bacteria. Symptoms include black or brown spots and streaks on the leaves and stalk of the plant. Again there is no cure but you can reduce the damage by ensuring that the plants have plenty of air flow and water them in a way that there is less splash back on the plant’s leaves.

Root Rot

Root rot can come from continued overwatering or from fungus in the soil. The fungus can be in the soil inactivated until the plant is overwatered a couple of times and then the fungus can spread. Whichever source causes the root rot, the roots of the plant will rot and die. When you plant your basil, make sure that is in an area that has good drainage and do not overwater your plants. You can tell if the plant needs water by looking at the top of the soil; if the soil is dry your plants need water.

On top of those problems here is another issue you may have with basil plants.

Nitrogen Deficiency

Nitrogen deficiency will cause your basil to be small and not grow well. All Plants need nitrogen as it is one of a plant’s building blocks, the same way protein is a human’s building block. If you think you soil has a nitrogen deficiency test the soil. If it tests low, you can add either organic or nonorganic treatments to correct the level. For example organic compost or a nonorganic fertilizer.

What are some other issues that can cause white blemishes on basil plants.

Before treating any issue with your basil or any other plants, always find out what you are dealing with. Find out what is the best treatment for that particular issue. And of course, always follow the direction on any treatment you use.

Preventing White Spots

Preventing white spots starts with planting your basil in a proper space where the plant will get plenty of sunshine and have enough airflow to help cut down on the dampness of watering.  Planting in the right area will cut down on the ability of mildew or fungus to grow.

Try placing landscaping fabric around in ground plants to prevent splash back on the leaves from watering. If your plants are in containers you can try using a water bulb that sticks in the dirt of the pot but remember those are used to consistently water the plant until the water in the bulb on the neck is gone and that could lead to overwatering causing root rot.

Use an insecticide, and if you want an organic insecticide, there plenty of them on the market, but you can also make your own insecticide.

One other way to help prevent white spots is to monitor the irrigation or rainwater your plants get. As stated, too much water causes dampness, a fertile breeding ground for fungus and mildew; but, too little water and plants will die.

When it comes to watering basil, you might be surprised to learn that it really does not take much. Approximately 1 inch of water a week is just right for most basil plants. However, plants grown in pots will need a little more than once a week.

Sometimes, no matter what you do, you will find that your plants develop white spots due to insects, fungus, or mildew.  When that happens, do not be discouraged. If your plants are grown in pots, clean it thoroughly with warm mild soapy water, and rinse thoroughly. Then allow them to dry in the sunshine. The next day, start new plants.

Is It Safe to Eat Basil With White Spots?

Yes, you can eat basil with white blemishes. Before you consume them just rinse the leaves in hot water. If you still aren’t sure after washing it, then cut out the white marks. You can also rinse the roots with an insecticidal soap, after doing this, just make sure you plant them in fresh soil. If you continue to see issues with the leaves then it’s often best to destroy the plant completely.

If a lot of the leaves have white spots, you may want to harvest them and dry or freeze them for future use. After harvesting, if the plant is in a container you may want to think about transplanting it to a new container (or into fresh soil when the previous soil has been contaminated with fungus). If you choose to transplant it, wash the roots of the plants so there is no dirt left from the previous soil. Inspect the roots, and if you notice any streaking take a sharp pair of scissors and trim the roots.

Recap

There you have it, many of the reasons your plants have white spots or streaks on the leave and stem. You also know how to take care of the basil to get rid of and prevent future infestations of insects, fungus, and other pests.

You also know now that it is perfectly safe to eat basil with white spots on it. Just wash it first or cut the spots out if there aren’t too many of them.

But, if you are still experiencing problems with white dots, pests, or getting your basil to grow, contact your local agriculture agency and ask them for more advice. Just don’t give up growing basil.

We hope our information has given you a little peace of mind and allows you to enjoy basil in many different recipes and cuisines.   

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