Black spots on peppers

Pepper Black Spot – Why Are There Spots On My Peppers

Even with ideal conditions and tender loving care, crops can suddenly be afflicted with a pest or disease. Peppers are no exception and a common malady is black spots on peppers. If the black spots are only on the peppers, the cause is usually environmental, but if the entire pepper plant is dotted with spots, it may have pepper black spot or other disease.

Why are There Spots on My Peppers?

As mentioned, if there are spots on just the fruit, the cause is probably environmental. Blossom end rot is a possible culprit. This starts as a small brown to tan spot at the bottom end of the pepper that feels soft or leathery to the touch. It is usually caused by inconsistent watering. Be sure that the soil stays moist an inch below the surface. General watering practices indicate an inch of water per week but depending on weather or if the pepper is in a pot, additional watering may be needed.

Sunscald is another environmental condition that may result in black spots on peppers. Sunscald is just what it sounds like – intense summer heat scalding areas of the fruit that are the most exposed. Use shade cloth or other shading material to cover the pepper plants during peak sun and heat in the afternoon.

Additional Reasons for Pepper Plants with Spots

If the whole pepper plant, not just the fruit, is being peppered by black spots, the culprit is a disease. The disease may be fungal or bacterial.

Anthracnose is a fungal disease that causes brown or black spots on fruit, and wet rot (Choaenephora blight) causes black growths on leaves as well as fruit. Generally, with fungal disease, once the plant has it there is no cure and the plant should be discarded, although fungicides can occasionally help alleviate symptoms. In the future, buy disease resistant plants or seeds and avoid watering overhead.

Bacterial diseases like bacterial leaf spot not only result in black spots on the leaves but a general distortion or twisting. Clear raised bumps appear on fruit and gradually turn black as the disease progresses.

Pepper black spot appears as round to irregularly shaped spots on mature fruit. These spots are not raised but the discoloration continues into the fruit. It is unknown the causal nature of black spot, but it is thought to be physiological.

To prevent black spots on pepper plants, always buy disease resistant varieties and treated seeds, water at the base of the plants, and shade them during the hottest part of the day. Also, use row covers to prevent pest infestation, be consistent with irrigation and fertilization, and plant peppers in well-draining soil.

Brown Spots on peppers

I would have said Blossom End Rot because that seems to be the most rot along these lines., and especially as you have it on a few of the larger fruit. It is caused by a Calcium deficiency. Check your MiracleGro – it is probably almost all NPK but might have Calcium in smaller quantities. Is that enough? I don’t know.

Usually the problem occurs more due to a mobility problem with the Calcium when watering is erratic – yes the plant might get water, but it might go a couple of days without water and then get it all at once. I have seen this and is probably hard to avoid with modern drought restrictions.

Ohio State have a Blossom End Rot Fact Sheet that is worth reading. As well as lack of Ca in the soil, and erratic watering, they mention “competitive cations”. What they mean is the pepper plant is absorbing similar ions to Calcium instead of Calcium – and then has a lack of calcium in the fruit. They mention ammonium specifically, but magnesium is probably a candidate (it is common, and is chemically very similar). Check your MiracleGro – if it is ammonium based, them this could be your cause. OSU’s recommendations are:

  1. Maintain the soil pH around 6.5. Liming will supply calcium and will increase the ratio of calcium ions to other competitive ions in the soil.

  2. Use nitrate nitrogen as the fertilizer nitrogen source. Ammoniacal nitrogen may increase blossom-end rot as excess ammonium ions reduce calcium uptake. Avoid over-fertilization as side dressings during early fruiting, especially with ammoniacal forms of nitrogen.

  3. Avoid drought stress and wide fluctuations in soil moisture by using mulches and/or irrigation. Plants generally need about one inch of moisture per week from rain or irrigation for proper growth and development.

  4. Foliar applications of calcium, which are often advocated, are of little value because of poor absorption and movement to fruit where it is needed.

When I’ve seen it, watering has been the main issue during drought conditions. Rot has not been too widespread. Pick the fruit before the rot gets too big. You can still eat it – just cut the rot off. If you wait too long, the rot will spread (secondary infections have taken over) and there’s nothing worth saving.

If you are seeing black spots on your peppers, you are probably wondering why it is happening. I was wondering the same thing, so I did some research to find out more. It turns out that the location of the black spots can help you to determine what is causing the problem.

So, why are your pepper plants getting black spots? Black spots on the fruit itself can be caused by blossom end rot, sunscald, anthracnose, or wet rot. Black spots on the leaves can be caused by black sooty mold, fusarium, bacterial leaf spot, or tobacco mosaic virus. Black spots on the stems can be caused by phytophthora blight or sclerotinia.

Let’s look at each of these causes in a little more detail, along with symptoms and treatments. Then, we’ll talk about how to do everything you can to prevent diseases in your pepper plants in the future.

Why Are Your Pepper Plants Getting Black Spots On The Fruit?

If your pepper plant has black spots on the fruit itself, then start here to determine the probable cause.

Blossom End Rot

Blossom end rot causes a dark, leathery spot to appear on the bottom or low on the side of a pepper. The spot starts off tan, and then turns brown and black. The spot may also become leathery or sunken-in.

BLossom end rot in peppers causes brown or black spots at the bottom of the fruit.

Blossom end rot usually starts at the first fruit set, and the problem also affects the fruit of others in the nightshade family (such as tomatoes and eggplants).

Blossom end rot is caused by calcium deficiency in the pepper plants. However, this calcium deficiency could be due to any of the following reasons:

  • Lack of calcium in soil
  • pH imbalance in soil
  • uneven watering (too much, too little, or both in combination)
  • excessive magnesium in soil
  • excessive ammonia fertilizer, or too much nitrogen – for more information, check out my article on low-nitrogen fertilizers.

Remember that you should not treat affected plants with Epsom salt (magnesium sulfate), since it contains no calcium at all. In fact, the magnesium can make the problem worse by competing with calcium for uptake by the plant’s roots.

For more information, check out this article from the University of Georgia on blossom end rot in peppers.

Sunscald

Sunscald first appears as white, tan, or yellow blisters on the fruit, usually on the side of the plant that gets the most sun. The fruit may also crack, and you will eventually see black mold growing on the sunscald patch, which explains the black spots you see.

Generally, sunscald occurs on the sides of the fruit (rather than on the bottom, as in blossom end rot). Sunscald can also affect tomatoes.

There is nothing you can do to change the amount of sunlight you get. However, when sunlight is intense, use row covers to protect exposed fruit from the sun’s harshest rays at midday.

For more information, check out this article from Missouri Botanical Garden about sunscald in peppers.

Anthracnose

Anthracnose is caused by the fungus Colletotrichum, and causes large brown or black lesions on pepper fruit. These lesions can appear anywhere on the fruit.

Anthracnose on pepper can cause black spots. Image from Wikipedia: https://commons.wikimedia.org/wiki/File:Pepper_Disease_in_Tropical_Bonakanda.jpg

Eventually, you will pink spores growing in the lesions. These spores can be spread by rain, and can survive the winter in soil or compost. Anthracnose can also affect tomatoes and other plants.

There is not much you can do to cure a fungal infection once it has taken hold of your pepper plant. Remove and destroy an infected plant and its fruit. Do not compost the material, since anthracnose can survive over the winter in a compost pile.

For more information, check out this article from Ohio State University on Anthracnose in peppers.

Wet Rot

Wet rot in peppers is caused by the fungus Choanephora cucurbitarum. It typically occurs in moist, humid regions. Dark gray or black growth of the fungus will appear on fruit, and the fruit itself may also rot and turn black.

Wet rot can also affect eggplant and other plants. For more information, check out this article from Seminis on wet rot.

Other Causes

In some cases, black spots on fruit can also be caused by cucumber mosaic virus or Phytophthora (more on this later).

Why Are Your Pepper Plants Getting Black Spots On The Leaves?

If your pepper plant has black spots on the leaves, then look here to find out what may be causing the problem.

Black Sooty Mold

Black sooty mold is a dark mold that looks like soot (from a chimney) that covers leaves and possibly stems of pepper plants. You can tell your plant has black sooty mold if you can scrape or wash away the mold.

Sooty mold looks like black powder or spots on a plant’s leaves, but it can be washed or scraped off.

For more information, check out this article from Mississippi State University on black sooty mold.

Black sooty mold is caused indirectly by aphids. When aphids feed on peppers (or other plants), they suck the juices out of the leaves and stems.

After they digest the juices, aphids leave behind a sticky and sweet waste product, called honeydew. The black sooty mold then grows and feeds on this honeydew and gives pepper leaves or stems a black appearance.

To prevent black sooty mold from affecting your pepper plants, take steps to get rid of aphids in your garden. One way is to spray them with a combination of water, dish soap, and alcohol. For more information, check out my article on how to get rid of aphids.

Fusarium

According to Wikipedia, fusarium is a wilt fungal disease, caused by fusarium oxysporum. Fusarium can cause wilting, chlorosis (yellow, discolored leaves), necrosis (blackening and death of plant tissue), leaf drop, and stunted growth.

Here we can see symptoms of fusarium wilt on a tobacco plant. Picture from Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Fusarium_wilt_symptom_tobacco.jpg

You will often see the tips and edges of older, lower leaves turning yellow, brown, or black first. This normally occurs later in the growing season.

You may also notice that only one side of a pepper plant is affected. Fusarium can infect tomatoes and other plants as well.

Fusarium prefers warm temperatures and moist soil, and it can survive for a long time in compost. If you see any infected plants, destroy them, and do not use the material in your compost pile.

Your best bets to prevent the disease are to plant resistant varieties and practice crop rotation.

For more information, check out this article from Wikipedia on fusarium.

Bacterial Leaf Spot

Bacterial leaf spot causes symptoms that vary depending on leaf age (location). It can also affect the stems of pepper plants.

Older leaves (lower on the pepper plant) will develop small “pimples”. Younger leaves (higher on the pepper plant) will develop water-soaked spots.

The pimples and spots later become tan or gray in the middle, with darker black edges. In warm, humid weather, the spots can get bigger. Unlike sooty mold, these spots cannot be washed or scraped away without harming the plant, since the bacteria has infected the leaf tissues.

The leaves of infected plants may turn yellow or brown, and then fall off. This lack of leaves can also cause sunscald on the pepper fruit, as mentioned earlier.

Bacterial leaf spot can be spread by rain or watering infected plants. This disease can also affect tomatoes.

There is no treatment, so remove and destroy infected plants, and do not compost the waste material. Use crop rotation, and avoid planting tomatoes and/or peppers in the same location in your garden every year.

For more information, check out this article from the University of Maryland on bacterial leaf spot.

Tobacco Mosaic Virus

Tobacco mosaic virus causes black areas on the leaves of pepper plants. The virus is spread by plant sap, and there is no known cure.

Here we can see symptoms of tobacco mosaic virus on orchids.

Infected plants should be removed and destroyed. Avoid working with your plants after touching or using tobacco products.

For more information, check out this article from the University of Massachusetts on tobacco mosaic virus.

Why Are Your Pepper Plants Getting Black Spots On The Stems?

If your pepper plants are getting black spots on the stems, then these are a few of the possible causes you should look into.

Phytophthora Blight

Phytophthora blight is caused by the oomycete phytophthora capsici. In addition to affecting stems, it can cause the roots and fruit of peppers to rot.

Here we can see the effects of phytophthora on a pepper plant.

Phytophthora is a devastating disease that can cause the loss of an entire crop. It can also affect tomatoes, eggplant, and other plants.

Pepper plants infected with phytophthora will display black lesions on their stems. In addition, fruit and leaves will wilt, but stay attached to the plant.

The fruit may eventually collapse due to rot, and the disease may spread to other plants by rain or watering. The disease may re-infect neighboring plants several times during one growing season.

To prevent phytophthora, choose pepper varieties that are resistant to the disease. Be careful not to splash water on leaves when watering, and plant peppers far enough apart to prevent easy transmission of disease. Also, be sure to use crop rotation to discourage the disease.

For more information, check out this article from the University of Massachusetts on phytophthora blight.

Sclerotinia

According to Wikipedia, sclerotinia sclerotiorium is a plant fungus that can cause a disease called white mold under proper conditions. Sclerotinia first causes pale to dark brown or black lesions on the stem at soil level.

Here we can see the white mold characteristic of sclerotinia.

The white mold later grows to cover these necrotic brown lesions. Afterward, symptoms spread up the plant, including chlorosis, wilting, leaf drop, and eventual death. The fruit can develop lesions if it comes in contact with the soil.

Sclerotinia can infect over 400 plant species. It can spread quickly from plants of the same type or different types.

To prevent the spread of sclerotinia, be sure to plant in well-drained soil and leave enough space between plants. Also, use crop rotation in three or four year cycles to discourage the disease.

For more information, check out this article from Wikipedia on Sclerotinia.

How Can You Prevent Peppers From Getting Diseases?

There are a few ways to prevent peppers from developing these problems in the first place.

Plant Disease Resistant Pepper Varieties

First, choose pepper plants that are resistant to diseases that are common in your area. Usually, the seed company or garden center selling the seeds or seedlings will indicate disease resistant in the plant description.

Use Crop Rotation

Make sure not to plant the same crop in the same part of your garden every year. Instead, switch plants every two, three, or four years to avoid the spread of disease. As an added bonus, this practice helps to prevent nutrient depletion in the soil.

Water Plants Close To The Ground

When you water your plants, water them more deeply and less frequently, to encourage the development of stronger root systems. Also, water during the day, not late in the evening when the leaves and roots are more likely to stay wet for a longer time. Otherwise, you risk root rot or fungal diseases on leaves.

Also, consider the possibility that you may be over watering your plants. For more information, check out my article on over watering your plants.

Remove Infected Plants

If you notice any infected plants, your best bet is to remove them to prevent further spread of the diseases. Destroy the plants instead of composting them, since diseases can often survive in soil or compost for a year or longer.

Conclusion

By now, you have a better idea of what might be causing black spots on your pepper plants. Remember that the location of the spots is one of the keys to identifying the cause. Once you figure out a probable cause, it is time to take action to rid your garden of the problem.

I hope you found this article helpful – if so, please share it with someone who can use the information. If you have any questions or advice about black spots on pepper plants, please leave a comment below.

What happened? – Chilli plants are developing spots on leaves and the edges are curling

You stated that you were using the following fertilizers:

  • Slow release NPK: 15.3%, 4.3%, 5.9%
  • General purpose NPK: 24.2%, 5.6%, 11.7%

Assuming your soil nutrients were balanced to begin with, the problem appears to be that you are using a very high-nitrogen fertilizer on peppers. Peppers, tomatoes and many other things prefer much less nitrogen than that. Most sources seem to agree that they prefer somewhat less nitrogen than phosphorus and potassium. I would probably recommend equal amounts of phosphorus and potassium, but I’m not an expert there, yet.

When nitrogen is proportionately much higher than potassium, it will inhibit the effect of potassium. Therefore, plants may get burned (like the tips of your leaves), and they may be more susceptible to disease and insects. They may also have reduced fruit size and be weaker. Nitrogen is supposed to encourage growth considerably, but in my experience with plants in the nightshade family, too much just makes the plants dwindle or have issues. However, some people report lots of green growth and little or no fruit when there is too much nitrogen (I’m guessing those people have more than window light or aren’t growing indoors like I am). Plenty of sunlight really changes the way plants respond to what, and it seems to increase salt tolerance. If you could increase your sunlight, it would probably help a great deal. Grow lights may help, too.

Anyway, I hope you didn’t use too much of that fertilizer.

To remedy the problem, you could add a fertilizer with no nitrogen in it (but plenty of phosphorus and potassium), such as 0-10-10 or 0-18-16, and after the imbalance is corrected, when fertilizer is needed again, use something like 10-12-12 or 18-18-21 fertilizer instead of your old fertilizer; occasionally 7-7-7 fertilizer should be good, too (especially if you need extra nitrogen). However, as I understand it, you shouldn’t need to fertilize peppers a terrible lot. Some say you only need to do it twice outdoors (once when you transplant them and once right after the fruit starts forming or so), but when indoors they may do well with more frequent fertilization (but probably not that much more frequent). I’m not sure why they would need it more indoors instead of less, however. That’s kind of counter-intuitive, unless it drains through the pots more. I’m guessing it depends on how water soluble your fertilizer is, among other things.

Alternatively (instead of the no-nitrogen fertilizer), you could wait until your plant uses a good amount of the fertilizer it has and then just use fertilizer, or whatever you choose, when it needs fertilizer again.

However, if you really want to know how much of what kind of fertilizer to add, get your soil tested first. It may not have been balanced to begin with.

Too much potassium is possible. I don’t know how much is too much, to be honest. But, if your leaves start getting yellow, you might need more nitrogen and maybe also more phosphorus.

About the insects, you might try dusting your peppers with some food grade diatomaceous earth. It’s a natural insecticide. Don’t get too much in the soil, though (although some is fine). Peppers don’t mind diatomaceous earth in the soil as much as tomatoes do, though. Tomatoes don’t really like it much, and they may wilt as a result (but may also recover eventually if it wasn’t too much). Also, you might consider neem oil to protect your plants from pests (but if your plants are outdoors, you should know that it may kill bees as well as pests).

Reports on Plant Diseases

Bacterial spot, caused by the bacterium Xanthomonas campestris subsp. vesicatoria, is the most common of all leaf and fruit diseases of sweet pepper in the Midwest. The disease is also frequently found on tomatoes in warm, rainy seasons with frequent or heavy dews. Fruit losses to peppers have approached 100 percent in some Illinois fields during warm, wet seasons, while losses in southern plant beds have been almost as high. Tomato fruit losses have been reported as much as 50 percent in fields. Besides pepper and tomato, the causal bacterium also infects black or deadly nightshade (Solanum nigrum) and groundcherry (Physalis minima).

Back to Top
SYMPTOMS

Distinct symptoms occur on pepper and tomato fruit, leaves, and seedlings and on pepper stems. Young leaves and fruit are more susceptible than older tissues.

Pepper

Infected plants in the seedbed have small, irregular, black spots, usually along the edges of the cotyledon leaves. Older plants develop small, circular, pale green, slightly raised spots (lesions) on the undersides of young leaves, with slight depressions on the corresponding upper surfaces. As the spots enlarge, they become straw-colored with dark brown margins. The center of the lesion often dies and collapses. As a rule the spots do not merge. On older leaves of plants in the field, the lesions are usually dark green, water-soaked, not noticeably raised, and up to 1/8 or 1/4 inch in diameter. Later, these spots develop dead, pale yellow centers with dark brown borders (Figure 1). When numerous, the lesions remain dark brown with a paler brown center on the lower leaf surface. Spotted leaves may turn yellow and fall at any time during the season. When spots are numerous, entire leaves drop off while still green. Seedlings infected in the plant bed may lose all but their top leaves.

Spots on pepper fruit are conspicuous, blisterlike, roughly circular, and up to 1/4 inch in diameter, with a cracked, roughened, or wartlike appearance (Figure 2). The spots are initially pale green but soon turn brown. During moist weather, various secondary, decay-producing bacteria and fungi enter through these lesions, causing the fruit to rot before or after harvest. Stem spots are small, raised, and up to 1/4 inch long. Eventually the cankers become roughened and light brown.

Tomato

Symptoms on young tomato plants are similar to those on peppers. Seedlings in seedbeds may be so severely spotted that the leaves turn yellow and drop. Leaf spots on older plants appear as small (1/8 inch), water-soaked, translucent lesions that later turn brownish black and may have a yellow halo (Figure 3). The lesions are somewhat irregular and appear “greasy” on the upper leaf surface with a translucent center and a black margin. The centers of the spots dry out and frequently tear. Spots are most numerous on the younger leaves. Only a few spots may cause a leaflet to turn yellow, wither, and drop prematurely. Lesions on the flower stems (pedicels) also cause the blossoms to blast and drop

Spots on green fruit first appear as small, black, raised “pimples” surrounded by a narrow, water-soaked border (Figure 4, right). Somewhat older spots are black, slightly raised, superficial, and up to 1/3 inch in diameter, with lobed margins and water-soaked borders (halos). Later, the raised center sinks, forming a rough, brownish black crater (Figure 4, left). Fruit spots are usually superficial and do not penetrate to the seed cavity. The spots continue to enlarge until the fruit matures. Ripe fruit are not susceptible due to their high acidity. Spotting of the fruit and dropping of the flowers are the most serious phases of the disease in the Midwest.

Back to Top

Large brown spots on peppers are not a disease problem and we don’t want you to spray because of them. However, there are some things that you can do to prevent these brown spots from happening.
We had some spots develop on our bell peppers in our raised bed test gardens. The brown spots we had were due to sunburn on the fruits. This happens to bell peppers in our hot desert climate. Try to get as much foliage on the pepper plant as possible before it starts to flower. That is difficult now because they have been breeding peppers to be more productive earlier in their lives which means they have less leaf biomass to cover the fruits and protect them from harsh sunlight.
Peppers are not the only vegetables affected by sunburn. Tomatoes can also develop sunburn.
Not a very good picture of tomato but they also will develop a brown, leathery spot on the side toward the sun.
A problem very similar in looks to sunburn can happen on tomato, peppers and eggplant fruits. This is due to irregular water content in the soil; the soil gets wet then too dry, then wet again and too dry.
It is believed this affects the uptake of calcium by the plant and causes a sunken, brown, leathery appearance on the BOTTOM of the fruit. This is called blossom end rot. We suggest that you mulch garden soils prior to hot weather to help keep the soil more evenly moist and prevent wild swings in soil moisture that contribute to blossom end rot.
Blossom end rot of tomato.
An excellent product to do this, better than straw, shredded paper or grass clippings is fresh horse bedding. This is a pine product that is shaved very thin and stays put when you apply it to the soil. We tested it this summer on our test beds and containers and it performed beautifully!

Leave a Reply

Your email address will not be published. Required fields are marked *