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Basil Plants Problems: How to Treat Pest and Diseases

Basil Plants Problems: How to Treat Pest and Diseases

Scientifically known as ‘Ocimum Basilicum’, the basil plant is one of the most versatile herbs in the culinary world. It’s a perennial herb that is native to India but is cultivated in many parts of the world. The holy basil tree has been used for thousands of years to make medicines and essential oils, and it continues to be used today as a means of treating ailments like indigestion, sleep problems, anxiety, and depression. In addition to its medicinal uses, this herb is also a staple in many different cuisines around the world.

Basil plants have a strong fragrant smell which makes them used in many dishes around the world.

It’s this fragrant smell that is why basil is used in many dishes around the world.

The herb is usually added towards the end of cooking, as it can lose its flavor and aroma if cooked for too long.

It’s commonly found in Italian, French, and Thai cuisine and is often paired with tomato-based sauces, such as marinara sauce and pesto sauce.

Basil also pairs well with fish, poultry, lamb, and pork.

Along with its pungent smell, basil has notes of aniseed and minty flavors.

Basil Plant Essential Oils Benefits

Though Basil Plant produces many uses and benefits, it is still not safe for pests and diseases that could make the plant die. This article will give you hints and ideas on how to identify and treat these threats in your garden.

Basil Plants Common Disease

Bacterial Leaf Spot

Bacterial leaf spot (or basil shoot blight) is a common disease that affects plants in the mint family. It can cause serious damage to your basil plants, but it’s easy to diagnose and prevent—as long as you know what to look for.

The most common cause of bacterial leaf spots is Xanthomonas campestris, which is spread through contaminated tools or water. The disease is more likely to affect young

plants and spread when the weather is warm and humid, though it can also take hold in colder climates if the conditions are right. It spreads easily through water splashing on the leaves, so it’s important to keep your plant’s foliage as dry as possible during watering.

The first sign of bacterial leaf spot is small yellow spots on the tips of leaves. As the infection progresses, these spots will turn brown and become more prominent on the underside of leaves than on top; they may even form a line along the veins. Leaves will often curl or turn yellow at this stage and become covered in slimy mucus. The stalks may begin to rot at their joints and produce dark lesions or black streaks, eventually leading to the death of the whole plant if left untreated.

How To Treat Bacterial Leaf Spot

There are a couple of things you can do to stop this disease from spreading.

Downy Mildew

Downy mildew is caused by a fungus that thrives in humid environments. If you have downy mildew, you will likely see grayish or whitish spots on the leaves of your basil plant. This disease can spread quickly and eventually turn the leaves yellow and cause them to fall off.

If you remove all affected leaves, it’s possible to salvage a basil plant with downy mildew. However, if the disease has spread beyond a few leaves, it’s best to completely remove the plant and replace it to prevent it from spreading further.

How to Treat Downy Mildew

You can treat downy mildew in basil plants with fungicides. Fungicides used in combination with good cultural practices are the best treatment for Downy Mildew. Look for a fungicide that is approved for use on basil and contains one of these active ingredients:

If you use copper, avoid using it on young or hot weather plants because copper is toxic to most plants. Neem oil works by preventing spores from germinating. Potassium bicarbonate also kills fungi but must be applied early before the fungal growth gets ahead of it. It has no residual effect, so reapplication may be required for two weeks or more until the disease is gone. Carefully follow all label directions when applying the fungicide and only apply in the morning when there’s still dew or moisture on the plant leaves so they absorb it better. Don’t get fungicide on your leaf surface; this will burn your leaves and damage them further!

Root Rot

The most obvious sign of root rot is wilting and yellowing leaves, though if you’re like me, you probably won’t discover the problem until your basil is drooping over the side of your pot. It’s not uncommon for a basil plant with root rot to lose its entire lower stem, and that’s nothing to panic about. It can be a good thing. Root rot can be treated by cutting off affected roots and repotting them into fresh, dry soil (wait a week before watering). Sometimes the soil has to be removed too, depending on how bad the rot is. As long as you remove all rotted material from your pot and sterilize any container or tool that came in contact with it, you should be able to save at least part of your plant.

Soil-based diseases are another common problem in container-grown basil plants. Overwatering is also a suspect. Water would then sit there around my plant’s roots, allowing bacteria or fungus already living in the soil to proliferate more easily than they normally would (they require moisture to grow).

How to Treat Root Rot

If you have discovered a basil plant with root rot, there are a few things you can do to try and save the plant. First, you should remove the rotting leaves from your plant and discard them properly by placing them in sealed bags. Next, it is up to you whether or not to attempt to save the plant itself. If it is not too severely rotted, then you may be able to salvage it by transplanting it into fresh soil with better drainage and less water. However, if the roots are badly diseased or rotted, the best solution is often to destroy the entire plant.

Basil plants that have been sickened by root rot should not be replanted in the same spot for at least one year as this increases the chances of reinfection. When planting basil indoors, make sure that all areas where water will drain (such as flower pots) have adequate drainage holes so that excess water can pass through easily. Overwatering is another common cause of root rot among basil plants– so avoid overdoing it!

Fusarium Wilt

Fusarium wilt is a disease that can quickly kill your basil plant. The presence of Fusarium oxysporum, the pathogen that causes the disease, often goes unnoticed until it is too late to save the plant. This is because the infection forms inside the stems, causing them to weaken and blacken over time. Leaves on infected plants may also turn yellow and fall off prematurely. If you suspect your plant has fusarium wilt, don’t fret: there are a couple of things you can do to diagnose and treat this common basil issue!

How to Treat Fusarium Wilt

Fusarium wilt is caused by a soil-borne fungus that thrives in warm, moist environments. The disease will first appear on the lowest leaves of your plant and eventually, move upwards. You can treat fusarium wilt with fungicide or try to prevent it from happening in the future by avoiding overwatering, using well-draining soil, and planting in the correct soil type for your basil plant.

The best way to treat fusarium wilt is to remove infected parts of plants and use a fungicide like Neem oil or Copper hydroxide on the affected plants. Remember to always spray both sides of leaves so that all areas are covered. If you notice that one plant is affected by Fusarium Wilt while others aren’t, you might want to rotate crops (plant something else there next year) instead of trying to replant basil in that same spot again next year.

Gray Mold

Gray mold, which is also known as botrytis cinerea and gray mold rot, affects a wide range of plants. This fungus can cause significant damage to your plant. It’s especially problematic because it thrives in cold and humid conditions, but even warmer temperatures are not enough to kill it off.

You can spot gray mold by looking for the fuzzy gray growth that gives the disease its name. You’ll typically see this coating on the underside of leaves. Another sign of infection is brownish spots along with wilting and yellowing leaves. If you see these symptoms, act quickly to stop the fungal growth from spreading throughout your plant

What Causes Gray Mold?

Bacteria can travel through either water or air currents, which means that it is entirely possible that your basil plant contracted gray mold from another plant in your house. In some cases, it’s even possible that the basil seeds could have been infected before they were planted. The fungus thrives in cool, damp conditions where temperatures are between 40 and 65 degrees Fahrenheit. Many people find that their basil plants contract the fungus during the winter months when they’re kept indoors to protect them from cold outdoor temperatures.

How to Treat Gray Mold

You can treat existing infections with fungicides or copper sprays, but it’s best to focus on prevention rather than treatment since this fungus can be hard to control once it starts growing on your plant. Make sure to keep humidity levels low around your basil plants so they don’t provide an attractive environment for this destructive fungus.

Basil Plants Common Pests

There are several pests you could have on your basil, and they can look very different. Generally, they look like little white-ish brown bugs that are almost translucent, so that you can see their insides through their outer shell. They will be in all sizes.

You may think that these pests were already in your garden dirt when you planted the seeds, but usually, this is not the case; usually, the eggs hatch after being laid by a female fly who is attracted to the smell of basil plants. The flies lay their eggs on the surface of the soil where your plant is growing, which means that pest control starts before you even plant!

Pests eat leaves from the bottom up, starting with older leaves and working their way up towards younger ones. This is why it’s important to start checking for them as soon as you see your first leaves appear.


Aphids on basil plants are small, pear-shaped insects that feed off the leaves and stems of your plant. They can be green, yellow, brown, black, red, or gray and usually congregate on the underside of leaves. They are most active during spring and summer.

Aphids suck nutrients from the leaves of basil plants, causing the foliage to become discolored and twisted. Because they feed by puncturing cells in the leaves and stems to suck out their contents until they burst, their honeydew excretions can also cause mold to grow on your plants.


To prevent the reoccurrence of Aphids on basil plants:


Basil is one of the most popular plants in an herb garden. It can be used in a variety of recipes and even as a natural insect repellant. However, one of the most common pests that target basil is grasshoppers. They like to eat basil and other leafy vegetables and herbs, such as mint, and can be hard to control. This is because they can jump away from

predators easily, so it’s difficult to fight them directly. Also, they are resistant to many pesticides! So what’s a gardener to do?

One option is using netting like this over your basil plants while they’re young. The net will keep grasshoppers away from the plants and allow you to monitor whether or not any have snuck under the mesh (if you see any flies or bees that should not be there). You’ll have no problems growing delicious basil for all your favorite dishes!


The adult grasshoppers are very easy to control. The most effective way is to use a pesticide like carbaryl, permethrin, or Abamectin. However, if you’d rather not use such chemicals, there are plenty of organic options available:

Fungus Gnats

Fungus gnats are the most common problem for basil plants. Adult fungus gnats lay eggs on the soil surface, and the larvae tunnel through the soil.

The fungus gnat larvae cause root damage that stunts plant growth and reduces yield. Fungus gnat larvae also feed on roots which can lead to wilting and stunting of new shoots.

The adults do not cause any harm to plants, but they are annoying pests that fly around your growing area. They can reduce the quality of your harvest by contaminating it with their excrement and saliva while they crawl over it looking for food or laying eggs.

What Causes Fungus Gnats in Basil Plants?

Fungus gnats are attracted to moist soil and decaying organic matter. If you have been overwatering your basil plants, this could be the reason why you have so many of them. Also, if you live in an area where it rains often, this can lead to fungus gnats as well. If you notice that your basil plants aren’t growing well or dying off quickly after planting them, then it could be due to fungus gnat infestation.


The first step is to remove the top layer of soil from the plant pot. This is probably where any fungus gnat larvae will be living. Then, you should wash the soil with water and pour alcohol over it to kill anything that might remain. Put some neem oil on the soil surface and wait for it to dry before adding more water to the soil. This will keep any fungus gnats from laying eggs in your potting mixture again!

You can also try using sticky traps around your plant pots to catch any adult gnats flying around looking for food or laying eggs on top of moist soil surfaces. These traps should be placed close enough together so that even if one falls off, there will still be others nearby catching them before they have time to escape from underneath the trap itself!


Whiteflies are common pests of basil grown indoors. They are not only a nuisance, but they can spread disease to plants and reduce their growth. Whiteflies are tiny insects about 1/20th inch long with wings that look like scales. They are white with black spots when viewed under a microscope.

Whiteflies feed on the underside of leaves by sucking out the juices and causing yellowing, stunting, and dropping of leaves.

Whiteflies may be present in the garden or greenhouse at any time during the growing season, but they usually become more active during warm weather.

What Causes Whiteflies in Basil Plants?

The main cause of whiteflies is no other than whitefly populations. These insects have a short life cycle and can produce many generations in one growing season. A single adult female can lay hundreds of eggs in her lifetime. It is not uncommon for a single plant to become infested within just a few days.


If you find whiteflies on your basil plants, try to isolate them from other plants as soon as possible. To avoid accidentally spreading whiteflies, always rinse off any dirt or debris before moving a plant indoors. Also make sure there isn’t any water inside the pot—if so, remove it immediately.

To prevent whiteflies from returning in the future, take steps to keep your home clean and free of clutter. Make sure all windows and doors are tightly closed when not in use; this will help prevent flies from entering your home through these openings.

Since you made it this far, come and take a look at the video below about Basil Care Guide – Pruning, Pests, and Disease. This would surely help you give the utmost care to the wonderful growth of your Basil Plants!

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