brown spot on pepper
Organic Gardening

Pepper Disease Management: Why do My Peppers Have Brown Spots?

It can be frustrating when you notice something is wrong with your plant, but you have no idea what it is. Sometimes brown or black spots on peppers can happen. What does it mean and can it be treated?

Journey with Growing Peppers

Growing peppers can sometimes be frustrating. They always seem to be a finicky plant for me to grow. They’re those kinds of plants that need the right conditions under no circumstances. Too much sun, they die, don’t grow, and/or they don’t produce fruit. Too much shade? Nope, don’t want that either. They want the conditions just right with the perfect balance of sun and shade. (At least in my experience). 

Knowing and understanding signs of disease is crucial to know so you can quickly find solutions to help out your plants. It’s the best way to have a successful crop and take precautions to keep your garden disease free too by taking preventative measures.

Why do My Pepper Plants Have Brown or Black Spots?

One factor to note before diagnosing your plant and treating it is to know what is a normal, healthy foliage, stem, and fruit. Peppers have green stems and leaves. However, along the stem you may see blackish areas. These black areas on the pepper plant are totally normal and not at all cause for concern. These darker areas are commonly found around the branches intersecting with the stem.

Occasionally, pepper plants can get brown or black spots on them that are not normal on the stems, leaves, and fruit.. What does this mean when this happens? Brown and black spots can appear on pepper plants for a number of reasons.

See below to see what causes these issues and how to treat the plant.

**Although there may be treatment to get these diseases under control, it is always best to practice preventative measures. Creating breeding grounds for diseases only opens you up to higher chances.

*** Some of these diseases have been touched upon in my post “How to Troubleshoot Pepper Growing Problems: Disease Management”. However these pertain specifically to brown or black spots on the plant.

DiseaseHow to ID it and what it doesHow to treat it
Bacterial Leaf SpotBacterial leaf spot occurs in warm, wet weather. It’s caused by a bacteria that starts on the bottom leaves where it’s more severe. The disease spreads by splashing wet soil onto the leaves. The leaves have round brown spots with dark edges. Spots can also be black and leaves are distorted. Fruit develops spots as well and raised cracks which open it up to pathogens. There is no way to treat bacterial leaf spot. Once there are signs of this disease, it’s too late. Destroy the crop and remove all debris from the plants. Do not compost the plants. Instead use preventative measures like crop rotation.
Phytophthora BlightThis type of blight is a fungal pathogen, which spreads in cool, wet weather. There are water soaked spots that form on the fruit and leaves. The whole plant, including the fruit, wilts and turns brown with a white coating that forms.Phytophthora blight is a soilborne disease. Practice crop rotation. Although sources tell growers crop rotation hasn’t been found to be successful in preventing this disease, crop rotation is always a good practice overall for disease prevention, in addition to other practices. Don’t plant susceptible plants in low lying areas.Don’t overwater plants.Plant disease resistant plants, and introduce no-till cover crops.Avoid soil compaction and that there is proper drainage of the soil.Avoid overhead watering. Water at the base of the plant using care not to splash water from the soil onto the plant.Remove diseased plants.
Blossom End RotIt is a physiological disorder that causes rotting on the bottom of the fruit  due to a malabsorption of calcium. Calcium is needed for the formation of cell walls. This can happen if plants grow too quickly. It also occurs if there is low to no calcium in the soil, the soil is too acidic, or has high levels of sodium, aluminum, and ammonia.Keep a consistent amount of moisture in the soil with watering. Ideally, a soaker hose or drip irrigation system should be put into place. However, if that’s not possible, ensure the plants get a deep watering. Apply mulch to your soil. There are various types of mulch that can be applied to your soil. Applying mulch helps to retain moisture in the soil, as well as prevent soil from washing away. Before planting seedlings, ensure the soil temperatures have warmed up. Cold soil will limit the plants’ nutrient uptake. Check the pH level of the soil and make sure it is about 6.5. Amend the soil with fertilizers and/or add calcium to the soil.
AnthracnoseAnthracnose is a type of fungal infection caused by the pathogen Colletotrichum coccodes. It loves warm, moist environments with poor air circulation. The disease starts out as small circular lesions that appear water-soaked, and develop a sunken, round appearance. It initially affects older leaves that are close to the ground. The infection is only evident on ripe and over-ripe fruit. Mature fruit develops black spots.
Take the following preventative measures:Plant disease resistant varieties.Keep foliage off of the ground. Any branches and leaves that are hanging towards the ground should be pruned off.Make sure soil is well draining, control weeds, and apply mulch heavily.
Pest InfestationPest infestations, such as from slugs, can cause brown spots on fruit. Pests invite infection and decay to the fruit and plant.  It’s important to stay ahead of pest control otherwise it can quickly get out of control and you can have an infestation. Infestations can damage not only the physical aspects of the plant, but also the overall health, rendering it vulnerable to other pathogens.For any pests in the garden there are a couple of natural things you can implement:Plant marigolds (they are commonly not liked by pests)Plant herbs that are companion plants to peppers. Herbs can mask the smell of the target plant.Use a mixture of water, non-toxic dish soap, and essential oils to deter pests.Spray down the plant with a strong stream of water.Use organic deterrents like diatomaceous earth, but keep in mind they can still harm beneficial insects.Consider deploying beneficial nematodes.Attract natural predators, like ladybugs.
Virus like Cucumber mosaic virus, potato virus Y, tomato spotted wilt virus There are a number of viruses that can stunt the plant, cause curled or deformed leaves, blotchy fruit or brown rings on fruit.Plant disease resistant varietiesKeep weeds. under control.Remove any debris that may be contaminated from the area and destroy the crop.Keep the thrip population under control.
Inconsistent WateringsInconsistent waterings can cause all kinds of stress on a plant. If the plant goes without water for long periods of time, it wilts. Overwatering can result in loss or malabsorption of nutrients and minerals that are critical from the growth of the plant and fruit, and may result in blossom end rot.Provide consistent waterings. If needed, set up a schedule when to water them. Peppers need 2 inches of water per week. You shouldn’t water the plant all at once with 2 inches of water. However, this may be unavoidable in rainy conditions.
OverwateringAs mentioned above, like all plants, peppers need consistent waterings. Overwatering the plant causes a malabsorption of nutrients like calcium.Wait until the soil dries out before carrying out the next watering. Mulch around the plant. Mulch can help regulate the amount of moisture in the soil so the plant doesn’t dry out too quickly, yet also retains water much more efficiently than bare soil.
OverfertilizingToo much fertilizer can hinder the absorption of other nutrients and minerals. An example is too much nitrogen and potassium causes poor absorption of calcium. Calcium is needed for the plant to form fruit with healthy skin. Without it, the plant develops brown spots.Before fertilizing the plant, thoroughly read the instructions on the label of the product. Only use the indicated amount on the packaging.

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