Basil is a culinary herb that is well-known for its nice smell. Healthy basil leaves are a vibrant green color.
Unfortunately, basil leaves can appear white from a range of insect infestations or fungal infections. Other causes of white spots on basil leaves invclude mundane reasons such as overusing fertilizer, overly bright light, or low nutrient levels.
Let’s take a closer look at why your basil leaves are turning white and figure out how to fix it.
What Causes White Spots in Basil Leaves?
Here are some of the common causes of white spots on basil leaves.
Downy Mildew
Downy mildew is the result of being in a wet environment for an extended period of time.
This explains why it usually happens during the rainy season and in warm and humid conditions.
Downy mildew is very contagious, and it can spread to healthy plants by the dispersal of spores carried in air and water.
- It begins with chlorosis, a reduction in chlorophyll involving yellowing in the veins of leaves.
- Eventually, the leaves develop white dots on the underside which turn into black lesions.
Early detection is the key to the solution for downy mildew.
If we do not catch it early, it moves through the plants, leaves drop, and eventually the plant dies.
White Fungus
Another reason why basil leaves develop white spots is a fungal infection.
This is similar to downy mildew and particularly prevalent during rainy seasons.
If the plants are getting too much moisture, the infection will increase.
The white fungus thrives in wet conditions. The first sign of the fungus is the standard fuzzy white outgrowths on the leaves that appear in concentric circles.
If untreated, they turn into a white mycelium cluster and spread throughout the entire plant.
In addition, white fungus may kill your crops a few months after the initial attack.
For this reason: It is best treated in its early stages and preventatively.
Applying too Much Fertilizers
If you use too much fertilizer on your basil plants, the effect will actually be negative.
The reason is that it increases the salt concentration in your garden, upsets the pH balance, and creates an environment, at the root zone, which is not supportive of plant roots.
Over time, the roots do weaken, and that stress impacts growth and development.
The roots suddenly no longer can absorb nor transport nutrients or water to other parts of the plant.
The end result, nutrient depletion inside of the plant, shows up as white spots on the leaf, and that can eventually kill the plant if you ignore it.
Too Little Sun
Should you find yourself in a region that receives limited amounts of sunlight, it is very likely your basil plants will develop white spots on their leaves.
The same thing happens if you plant your basil indoors away from natural light.
Sunlight is essential for various processes like transpiration and photosynthesis.
It’s important for these processes; if you do not get enough sunlight, your plants will develop white spots and they may even die as a result of lacking nutrients.
Incorrect Watering
An additional reason for your basil leaves becoming yellow or white is due to overwatering your plant.
When you overwater your plants, you’re at an increased risk for root rot.
When we say root rot, we refer to the plant’s roots becoming dark brown and preventing the plant from absorbing nutrients.
Once the roots decline, the poor health spreads to other parts of the plant. Yellowing or whitening of the leaves in the plant’s lower branches occurs, and the plant will begin to decline entirely.
Pest Infestations
Pests can cause white spots and various other conditions that may kill your basil plants by stealing nutrients from them.
Below are some examples of how these organisms can damage your plants.
- Aphids: They’re usually found on the underside of your plant leaves, sucking out juices and showing discoloration.
- Caterpillars: They tend to target the leaves and munch away at them.
- Thrips: These pests like to invade buds and the underside of leaves. They often leave behind leaves that are silvery brown, indicating that they attacked your plant.
How Do You Treat White Spots in Basil?
The best approach to obtaining optimum results when dealing with white spots on basil depends on the cause.
In this regard, you can use different treatments for a plant that is affected by a disease or by a pest.
What Methods Are Used to Deal with Diseases?
In the case of fungal infections, if the basil leaves are turning white, you can treat it by using fungicides.
Simply follow the instructions that come with the chemical or product.
With bacterial infections, there is no cure. The only remedy for these problems is to uproot the affected plants and dispose of them properly.
Here are some other remedies you might try to treat the diseases in basil.
- Baking Soda: this home remedy is made with a combination of baking soda, dish soap, vegetable oil, and water. This remedy is best applied on watered plants as it may burn up leaves if applied on dry foliage.
- Potassium bicarbonate: this works essentially the same as baking soda but is particularly effective when fighting mildew and fried.
What Methods Are Used for Fighting Pests?
Sometimes, white spots might be a result of pest attacks.
Here are the methods you can use to treat them:
- Employ appropriate irrigation techniques: you want to avoid over watering because this can lead to the development of mildew.
- Maintain sanitary conditions around your plants: clean plants are an effective measure to discourage insects, but that entails ensuring that dirt does not accumulate on your leaves.
- Relocate your plants indoors: if you do not think your plants are receiving sufficient light, you would consider relocating your plants into the indoors. The takeaway here is to avoid transferring your plants into the outdoors for too long.
- Use neem oil: as unpleasant as it smells, neem oil works in the killing of pests on your basil. Do not get carried away with the neem oil though, as it will change the flavor of your plants.
Final Thoughts on What’s the Best Way of Preventing Future Attacks?
If you are looking for a long-term fix to the white spots issue, I suggest adhering to proper planting techniques.
Do not overcrowd your plants and ensure you have a proper irrigation system along with checking your soil content and hygienics.
Lastly, replace nutrients regularly. Nutrient deficiency can discolour the plant leaves and stiffen the plant against adverse conditions, such as white spots.
If the deficiency continues, the leaves die and become white. This is a detriment to the plant’s health overall, and them, themselves become useless and unsafe for humans.