Growing peppers is a lot of fun, but it doesn’t always work out perfectly. Some years, harvests can be significantly reduced by unforeseen pepper plant diseases or problems.
Here, we will share some of the most common pepper plant problems, how to identify them, and how to prevent issues in the future. Some diseases are irreversible, other issues can be dealt with within a single growing season.
While this is not an exhaustive list of pepper plant diseases and problems, it covers the most common issues we are asked about by our fellow pepper growers.
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In This Article
- Bacterial leaf spot
- Mosaic virus
- Verticillium wilt
- Blossom end rot
- Yellowing leaves
- Curling leaves
Pepper Leaf Spot
Pepper leaf spot is a common bacterial plant infection seen all around the world. It is most common in rainy, humid and warm climates. These are the environmental conditions in which the bacteria can spread most easily.
Leaf spot is a bacteria, so it can be spread by touch, through seeds or via soil. Use cleanly soil and watering practices to avoid splashing the leaves with soil or cross contaminating.
- Yellow and green spots on leaves
- Brown spots on leaves in later stages
- Raised, corky spots on peppers
- Leaf drop and decaying peppers
Remove infected areas. As with pepper plants infected with viruses, you should remove parts of the plant that show signs of leaf spot. The bacteria can spread easily, especially under damp and hot conditions. You don’t need to remove the entire plant unless it is totally covered.
Provide adequate fertilizer. With proper nutrition, pepper plants can actually fight off the bacteria. As with humans, the more healthy we are, the more able we are to fight off bacteria quickly. Feed any affected plants with a high quality fertilizer, consistently.
Spray with natural fungicide. Although leaf spot is bacterial, fungal treatments have been known to help. Use a copper based fungicide as a foliar spray in the early morning or late evening to help reduce the spread.
Avoid wetting the leaves when watering. Water is necessary for the spores to multiply and spread on your pepper plant’s leaves. Always water at the base of the plant to avoid splashing water on the leaves.
Practice cleanly gardening. As with all bacterial and viral pathogens, it is important to be cleanly while in the garden. If possible, use gloves when handling your plants. Avoid touching all of the plants one after the other to avoid spreading any bacteria.
Mosaic Virus On Peppers
Another very common pepper plant issue is mosaic virus. There are many different types of mosaic virus, and once a plant is infected, it is irreversible. Some pepper varieties are resistant to tobacco mosaic virus, while none are resistant to cucumber mosaic virus.
Mosaic viruses can be seed borne or soil borne and are spread by sap sucking insects such as aphids. They can also be spread by contact of infected plants, and are most problematic in dry weather.
- Green and yellow mottled leaves
- Prickly or bumpy surface on fruits
- Stunted growth
- Low pepper production
Remove affected plants. There are no effective treatments for viruses. If you suspect mosaic virus, remove the pepper plants from the garden and burn them if possible. The fruits are still safe to eat, but the seeds can carry the virus, so do not save seeds from affected fruits.
Keep the weeds under control. Weeds can carry mosaic virus, and can also be a breeding ground for the insects that spread it. Use a ground cover, or at least keep the weeds at bay with a weeding hoe (these are great for saving your back).
Avoid touching plants. Always wash your hands before and after gardening. Your hands can be the vehicle to transfer viral pathogens from one plant to another. Also, avoid smoking in your garden, as this can introduce mosaic virus to the soil.
Plant resistant pepper varieties. Some varieties have been identified to be more resistant to tobacco mosaic virus, though none are resistant to cucumber mosaic and other viruses. Look for varieties that are labeled ‘TMV’ (tobacco mosaic virus resistant) at nurseries and garden centers. Some common types are jalapeno, sweet banana, super cayenne, and bell boy hybrid.
Blight On Peppers
Phytophthora blight is a pepper plant disease that is spread by a soil-borne pathogen. If your pepper plants have leaves low on the main stem, the rainfall can cause the soil to splash up on to the foliage, spreading the disease.
There are more than one type of blight, usually categorized into ‘early blight’ and ‘late blight.’ Symptoms are similar, but some are more common in different parts of the world at different times of the growing season.
There are many other plant varieties that are susceptible to blight, including tomatoes, eggplant, beans and all types of squash.
- Large, brown leaf spots and wilting
- Brown or black stems at base of plant
- Root rot (leading to plant death)
- Fruit rot (when in contact with infected soil)
Plant your peppers in a raised bed or in pots to improve drainage. Blight is most commonly found in in-ground gardens or fields. Rainfall will have less time to sit on the surface of the soil and spread the pathogen in a raised bed or a potted plant.
If you can’t use a raised bed or pot, always mound up the soil around each plant to avoid standing water at the base of the plants.
Another step to take is to use a ground cover, such as a black tarp, straw or mulch. Ground cover helps prevent splashing from the soil onto your pepper plant’s leaves when it rains. It also has other benefits like improved water retention and subduing weeds.
If it is dry, do not over-water your garden. Standing water is the only way that blight mold spores can multiply and spread. Wherever the infected water flows, the spores will follow.
Always acquire your soil and/or compost from trustworthy sources. Bringing infected soil into the garden is the easiest way to end up with this pepper plant problem.
Verticillium Wilt On Peppers
Bacterial wilt is an issue that can effect pepper plants along with many other vegetables. It is commonly found in former tobacco fields, and can wreak havoc on entire crops if not caught early. It is most common in the southeast US.
The bacteria plugs up the vascular tissue of the plant, making it impossible for water to be transferred throughout the plant. Typically, pepper plants infected with verticillium wilt will begin to wilt on one side of the plant first.
As the bacteria grows, the plant will eventually collapse and die. If it is discovered, this pepper plant problem should be dealt with immediately.
- Yellowing and wilting leaves, sometimes starting on one side of the plant
- Vascular discoloration (inner tissues of the stems turning brown)
- Fully collapsed plants (death)
Water your plants. The most common reason for pepper plants wilting is simply a need for water. Don’t over-react to wilting, assume it is bacterial wilt, and rip up your plants! Try some water first, and if that doesn’t solve the issue in an hour or so, investigate further.
Remove affected plants. As with most diseased plants, the first step is to remove and destroy affected plants.
Control pests. Cucumber beetles and other insects can spread bacteria from one plant to another. Learn how to identify and control these pests and others to keep bacterial wilt from spreading and persisting in your pepper garden.
Add beneficial bacteria in soil. Using beneficial bacteria has been shown to be effective at treating bacterial wilt. This method may be better suited for professional farmers who grow peppers and other veggies.
Pests On Pepper Plants
Pests can cause significant damage to pepper plants on their own. From aphids to spider mites to thrips, the list of pepper plant pests is long. Thankfully, there are preventative measures you can take against most of them.
- Visible pests (check under leaves, on stems, etc.)
- Leaf damage
- Dark spots on leaves
The type of pest will often determine the best solution. Sometimes, you can simply remove the pests, as with tomato hornworm and other caterpillars. However, others are small and come in large numbers to feast on your pepper plants.
Spray with a hose. Aphids and other small sap sucking insects don’t have a tight grip on your plant. By spraying the leaves directly with water, you can knock a majority of the pests off of the plant. This isn’t a permanent solution, but it can slow them down.
Spray with neem oil. Spray your pepper plants using a solution of 1 tbsp pure neem oil, 1 tbsp castile soap, and 6 cups of water. The neem oil is all natural and will kill active pests and deter new ones from joining the party.
Introduce beneficial insects. Lady bugs are some of the most common beneficial garden bugs. Introduce the live ladybugs to your pepper garden in the evening when the sun is going down to avoid them flying away. The ladybugs will stay and feast on aphids and other sap suckers.
The list of pepper plant pests is lengthy, and this is in no way a complete guide to controlling them.
Blossom End Rot On Peppers
Blossom end rot is most common on tomatoes and large sweet pepper varieties. It is primarily caused by a lack of calcium within the plant which leads to an inability to form the fruit’s skin. It is not actual rot, but just an underdeveloped fruit.
The pepper skin will develop dark, soft spots, usually on the bottom of the fruits. This vulnerable skin invites mold to grow, making the affected part of the fruit inedible.
- Soft spots on bottom of pepper pods
- Shriveled and dead skin
- Mold inside of peppers
Provide calcium. Without adequate calcium, pepper pods will not be able to produce skin properly. This causes blossom end rot, but it can be resolved by adding calcium.
One of the most common issues pepper growers face is the dreaded yellowing leaves. While it is usually not a big deal, there are measures you need to take to correct this pepper plant problem.
- Yellowing leaves
- Leaf veins turning yellow
- Leaves falling off
While the solutions to yellowing leaves will vary depending on the cause, here are a few potential fixes.
Provide nitrogen. Nitrogen is an essential nutrient for healthy plant development. It helps pepper plants grow lots of big, strong green leaves. Make sure you are fertilizing regularly and that your fertilizer contains enough nitrogen.
Tip: If the problem is nitrogen, the yellowing leaves will begin at the bottom of the plant, moving upwards over time.
Provide magnesium & calcium. A magnesium deficiency will cause chlorosis when severe, meaning the veins of leaves will remain green while the rest turns yellow. Use a cal-mag spray or use soil amendments like bone meal and blood meal when planting peppers. Many fertilizers also contain these secondary nutrients.
Don’t over-water. Over-watering is another possible reason for pepper plants turning yellow. Be sure to only provide water when necessary. Peppers prefer to be on the dry side, so use a moisture meter or allow the first inch of soil to dry between waterings.
Here is a problem faced by first-time and veteran pepper growers alike. With so many possible causes, treating curled pepper leaves can be tricky.
Most of the time, curling pepper leaves is a sign of either a calcium deficiency, too much light, too much water, or plant edema. There are diseases that can cause curled leaves, but if the plant appears otherwise healthy, it is most likely one of these causes.
- Curling leaves
- Distorted leaves
- Stunted growth
Provide calcium. Pepper plants require calcium in order to properly form strong cell walls. This is what gives the leaves and pepper pods their symmetrical, uniform shape. When calcium is deficient or missing, the leaves and fruits may distort.
Provide calcium via bone meal during potting or a foliar cal-mag spray. Many fertilizers also contain calcium.
Move grow lights up. If you are growing peppers from seed indoors, your grow light may be too close to your plants. If you are using an LED light, it should probably be at least 12-15 inches from the plant leaves. Read up on your specific light unit and be sure that your plants have enough space.
Increase airflow. Plant edema is caused by environmental conditions, especially poor air circulation. If your plants appear to have white crystallized bumps along the underside of leaves, they may have edema. Increase airflow with a fan if indoors, or by spacing peppers farther apart outdoors.
Don’t over-water. We’ll say it again, over-watering is bad! Don’t provide too much water for your pepper plants. It can cause curling leaves, too.
I hope this article helped you diagnose your pepper plant problems. While these are by no means the only issues you may have with your pepper plants, it is definitely the most common problems we have seen.
Keep a close eye on your plants, look out for any changes, and most importantly, keep them healthy and happy with enough nutrients, water and sunlight! Happy pepper gardening.