The tiny black spots on your pepper leaves are a common problem. This article will talk about the causes and how to eliminate them.
What Are Tiny Black Spots On Pepper Leaves? Like other vegetables, pepper plants are prone to some insects and diseases. Sooty Mold, Bacterial Leaf Spots, and Mosaic Virus are diseases that can cause tiny black spots and discoloration on pepper leaves.
What Causes Black Spots On Pepper Leaves?
There might be several reasons for tiny black spots on your pepper plant leaves. The 3 main reasons are:
So, let us discuss each in more detail.
Sooty Mold
Sooty mold is a fungal disease responsible for the black spots on pepper leaves. Typically, it grows on plant parts covered with honeydew. The mold resembles soot from the chimneys, and it causes a black appearance on the pepper plants.
From tiny black spots to large black splotches, the pepper leaves infected with sooty mold usually mean an infestation of pests.
These specific pests such as aphids, whiteflies, leafhoppers, or mealybugs produce honeydew.
Honeydue is a sugary waste excreted by these insects, producing a black-colored fungus on leaves or anywhere else where the honeydew drops.
While the sooty mold does not directly infect the plant, it can coat leaves and block the light from plants. This will slow down the photosynthesis and the growth of peppers.
Also, the leaves affected by sooty mold are more susceptible to other diseases.
Early symptoms of sooty mold on pepper plants are:
- Tiny black spots on leaves or stems. It is sooty mold if these spots can be wiped off and feel sticky when touched.
Sooty Mold Management
Most plants can tolerate small amounts of sooty mold and pests. However, the problem of sooty mold usually occurs when the population of pests increases and there is too much sooty mold for the plant to handle.
There are many ways to control sooty mold.
- Stop it at a source. Control honeydew-producing pests such as aphids, whiteflies, leafhoppers, mealybugs, psyllids, and soft scales. Use organic insecticides such as neem oil, garlic spray, or insecticidal soap.
- Attract beneficial insects. The best way to control pests is to attract beneficial predatory insects that feed on them. Beneficial insects include ladybugs, hoverflies, green lacewings, assassin bugs, minute pirate bugs, parasitic wasps, praying mantis, and spiders.
- Wash the sooty mold off. Once the pest population is reduced, the sooty mold will slowly lessen. Use a stream of water or soap to wash off the pepper leaves. [1]
Pro Tip: Don’t let ants near honeydew. Ants consider this sugary liquid a food source. So, they will herd pests that produce honeydew and protect them.
Mosaic Virus
Mosaic viruses can affect pepper plants causing distorted appearance and mild to moderate mosaic-like spots on the leaves. The spots are often irregularly shaped and may be sunken.
While black spots on the leaves are not the first sign of this disease, they could appear during the later stage.
The mosaic virus doesn’t kill pepper plants. Instead, it slows down the growth and reduces the harvest.
A few strains of the mosaic virus can affect pepper plants. These are Cucumber mosaic virus (CMV), Tobacco mosaic virus (TMV), Alfalfa mosaic virus (AMV), and others.
They have different names but similarities in the symptoms. Some virus strains can be transmitted by insects such as aphids or leafhoppers. Others, through seed and mechanical spreading by contact.
Early symptoms of the mosaic virus on pepper plants are:
- Light and dark green leaves exhibit irregular mild to moderate mosaic patterns and a dull appearance,
- Wrinkled or curled leaves,
- Stunned growth of pepper plant,
- Wilting of the plant,
- Yellow and brown spots can turn black over time.
Mosaic Virus Management
There is no cure for the mosaic virus on pepper plants. If you notice mosaic virus symptoms, discard the infected plant parts as soon as possible. Do not compost them! [2]
You can take some precautions to reduce the spread and survival of this virus.
- Cover the seedlings to protect them from the pests transmitting the virus.
- Plant trap crops such as mint, mustard, dill, nasturtium, and milkweed to divert pests that transmit the virus from the main crop.
- Grow plants around you pepper that repel these pests. These are onions, garlic, and marigolds.
- Avoid touching any healthy plants after handling a plant that is affected by a mosaic virus.
- Wash and disinfects your hands and tools after pruning or handling the infected plants.
Pro Tip: Use disposable gloves when handling infected plants. Gloves will keep your hands clean.
Bacterial Leaf Spot
Bacterial leaf spot is a common disease of peppers. The first symptom of bacterial leaf spots appears as round water-soaked lesions on leaves. The lesions turn brown or black and may enlarge over time.
Once the infection starts, it is hard for plants to survive. In severe cases, bacterial leaf spots can devastate the whole pepper crop.
Bacterial leaf spots are spread mainly through the contaminated seeds. The disease can also spread through contaminated tools or splash from one plant to another by irrigation or rain.
Primary symptoms include disfiguration of the fruit and early defoliation. However, you can destroy the plant before others get infected by noticing signs early. [3]
Early symptoms of bacterial leaf spots on pepper plants are:
- Water-soaked lesions on leaves that enlarge and change color quickly from green to dark brown.
- The spots dry in the less humid weather, and some of the infected tissues fall off, resulting in the torn appearance of leaves.
- The leaves of the infected plants turn yellow and fall off. This exposes the fruit to sunscald.
Bacterial Leaf Spot Management
The damage caused by bacterial leaf spot disease is irreversible. There is no treatment, so you must destroy the infected plant parts. Do not compost them!
Avoid planting peppers or tomatoes the next growing season in the same area.
You can take some precautions to reduce the spread and survival of this bacteria.
- Use resistant pepper varieties.
- Treat seeds before sowing with hot water. Soak them for 30 minutes in water of 125oF (51oC). This method will reduce the population of bacteria on the outside and the inside of seeds. The drawback is that germination can be affected if the treatment is performed incorrectly.
- Rotate crops. It is an effective way to prevent the bacteria from affecting the following year’s crops.
- Use drip irrigation or water the soil. Avoid overhead watering. This will reduce the chances of bacteria spreading through splashing.
Pro Tip: This disease does not cause fruits to rot. But, it can open a path through lesions to other pathogens that can decay all or some of the peppers.
How To Treat Black Spots On Pepper Leaves?
In some cases, you can treat black spots on pepper leaves. However, mosaic virus and bacterial leaf spot diseases have no cure. You can prevent black spots on pepper plants by following these tips:
- Select disease-resistant varieties of peppers. When purchasing, you can check the disease-resistant properties in the description on the seed packet.
- Avoid watering the leaves of pepper plants. You can prevent disease spread if you water plants close to the ground. Also, allow the soil to dry between watering intervals.
- Practice crop rotation in your garden. Planting the same crop in the same area of your garden each year will keep the disease alive. So, changing crops every two to three years will prevent disease and solve the soil’s nutrition depletion problem.
- Keep monitoring your pepper plants for black spots. Take action as soon as you notice the infected plant parts. Discard the infected leaves to stop the disease spread.
- Never place infected plants into your compost.
Wrapping It Up
Bacterial leaf spots and the mosaic virus can be responsible for black spots on pepper leaves. But before you start worrying about those, look at the underside of the leaves. You could be looking at sooty mold if there are many aphids or other honeydew-producing insects, which is not as bad as the other two diseases!
Hopefully, you found the cause, treatment, and prevention of tiny black spots on pepper leaves after reading this article.
If you enjoyed reading this, check out other similar articles in our Gardening How To section.
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