Pepper Plant Problems: How to Deal With Pests, Disease, and Other Setbacks
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Summer is a challenging season for growing, since it’s prime time for just about every living organism that wants to trash your garden. Thankfully, pepper plants are more resilient than other crops against the different things that can go wrong during heat wave and bug invasion season. There are, however, a handful of problems that can show up in your pepper patch.
Pepper plants are vulnerable to a few pests and diseases, as well as some environmental issues that can negatively affect your harvest. None of these are typically devastating, though, as long as you spot them early and intervene if necessary.
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Pests
A few different insect pests might come after your pepper plants. Most are more a nuisance than a major threat to your crop, but several of these guys might merit some action to prevent losses.
Spider Mites, Aphids, and Thrips
We’ll throw these in the same category, since control is similar. These tiny bugs can cause deformed new growth, curling leaves, and stippling or discoloration on the leaves from feeding. Aphids and thrips sometimes transmit viruses.
Insecticidal soap or neem oil solution can work to control infestations of these squishy little bugs. However, spraying often isn’t necessary. These insects cause the worst trouble for new transplants, when the plants are trying to establish and dealing with some stress. Sometimes, feeding the plants with some water-soluble fertilizer will sort the problem out.
Planting companion flowers to attract predatory insects also works well to control small sap-sucking pests. That bug diversity makes your garden more appealing to spiders, too. You’ll be surprised how effectively nature can take care of a pest problem when you work to make your garden an ideal habitat for beneficials.
Stink Bugs and Leaf-Footed Bugs
These jerks are only after the fruit, and you won’t see evidence aside from the bugs themselves and the dry, white blotches on your peppers from their feeding. They’re hard to control with insecticides (natural or not), so the best defense is to seek and destroy.
If you’re seeing a lot of damaged peppers, go on a raid once a day and knock any bugs you see into a cup of soapy water. Squishing stinkbugs is not for the faint of heart, since, well…they stink.
Caterpillars
Tomato and tobacco hornworms, armyworms, and tomato fruitworms are all partial to pepper plants as well as tomatoes. You’ll see their black droppings on the plants (frass) and conspicuous holes in leaves and fruits. Of these, hornworms are the most damaging, since they can skeletonize a whole plant within a few days if left to their work.
Scouting regularly and hand-picking once you’ve noticed a problem works well to control caterpillars. For bad infestations, you can spray Bt (Bacillus Thuringiensis), a natural insecticide that targets caterpillars and won’t hurt most other beneficial insects. Use caution with Bt if you have host plants for butterflies in your garden, as Bt is very toxic to butterfly caterpillars as well.
Slugs
If you have them around, slugs are one of the most destructive pests for pepper seedlings. They like to eat the new growth, which is bad enough as it is. I’ve also seen them break seedling stems at the top while climbing up to reach the tender baby leaves. In the worst case scenario, they can eat a whole seedling overnight. The good news is that slugs aren’t much of an issue once the plants get bigger.
Beer traps, Diatomaceous Earth, and iron phosphate baits like Sluggo are effective and organic-approved options to protect pepper seedlings from slugs. All of those work best when combined with careful monitoring. Check your plants in the mornings and after rainy weather and pick off any straggler slugs.
See this post for more about dealing with a slug problem: Controlling Slugs in the Garden: 5 Natural Methods That Actually Work.
Cutworms
If you go out to the garden in the morning and find a few of your pepper seedlings toppled over and gnawed through near base of the stem, one of the several nocturnal caterpillars known as “cutworms” was probably responsible. As you’d expect, seedlings don’t often recover from a cutworm visit.
These caterpillars are infuriating but pretty easy to work around, once you learn the hard way that you have them. Collaring your seedlings with a piece of a paper towel or toilet paper roll is usually enough to thwart a cutworm. Another option: just plan to let your pepper seedlings get a little bigger indoors before transplanting so the stems toughen up. Cutworms much prefer the tender stems on younger seedlings.
Diseases
Peppers aren’t nearly as prone to disease as most other garden plants. But under the right conditions, they’re susceptible to a few fungi, bacteria, viruses, and other environmental problems.
Leaf Spot on Pepper Plants
Bacterial Leaf Spot is the most common issue you’ll run into, especially if you’re having a lot of wet and humid weather. It causes irregularly shaped brown spots on leaves, followed by yellowing and leaf drop. BLS can also infect the fruits; this looks like small, black pimples on the outer skin.
Some sources will tell you to yank plants that develop bacterial spot symptoms. This disease is common where I live, and I’ve never removed plants because of it, since most affected plants still produce good-quality peppers. Any little spots on the peppers themselves don’t often affect the flavor or firmness of the fruit. You can cut them away, and the peppers are perfectly fine to use.
Bacterial leaf spot will often go into “remission” when drier weather arrives.
Cercospora (Frogeye) Leaf Spot causes round spots with white centers on pepper leaves, followed by yellowing and leaf drop on badly infected leaves. It doesn’t directly affect fruit, but major cases can defoliate the plant, leading to poor production. Cercospora is also favored by wet weather. The spread will slow down with drier conditions.
If you catch these leaf spot diseases early, you can remove infected leaves to slow down the spread. However, it’s important not to strip an affected plant of too many leaves at one time. Doing this can shock the plant and drastically lower its natural ability to fight the disease.
When your peppers get a case of leaf spot, make sure to regularly collect and dispose of any dropped leaves to keep the spores or bacteria from building up in the soil.
Fungal and Bacterial Wilts
Tomatoes and cucurbits like squash and cucumbers are much more prone to wilt diseases than peppers, but pepper plants do fall victim to it every now and then. Fungal wilts like Fusarium are soil-borne, while bacterial wilt is typically spread by insect feeding.
Peppers are pretty heat tolerant plants. While a little drooping is normal on a hot afternoon, any unexplained and severe wilting, especially if it’s isolated to one plant, is reason to investigate. Keep an eye on it and see if it recovers by evening. If not, check to see if the soil is too dry and water if needed. If the plant still doesn’t bounce back, suspect bacterial or fungal wilt.
It’s hard to tell exactly what type of wilt you’re dealing with. In any case, it’s best to quickly remove a plant that wilts and doesn’t recover. That way, it doesn’t provide a source for more disease spread in the garden. Thankfully, wilts usually strike at random, only affecting one or two of your pepper plants during a season.
Fungal wilt diseases can also cause damping off (collapse and death) of seedlings, but this is more likely with small seedlings in seedling trays, not large, sturdy transplants.
Viruses
Pepper plants can catch viruses, such as Tomato Spotted Wilt Virus, Tobacco Mosaic Virus, Pepper Mild Mottle Virus, and Cucumber Mosaic Virus (to name a few). It’s hard to tell one virus apart from another, without lab testing. But the usual symptoms are ringspots or mosaic (weird spots or patterns) on the leaves and/or fruit, deformed new growth, and dieback of the growing tips.
Most viruses are transmitted by pest insect feeding. Thrips are particularly bad for carrying Tomato Spotted Wilt Virus, which is one of the most common viruses to show up in folks’ backyard gardens. Since our garden is located between the woods and a thicket of native weeds and flowers, we have a lot of trouble with thrips. We see TSWV pop up almost every year. Fortunately, it only affects one or two plants within a season.
If you’re certain your plant has a virus, it’s time to pull it out and take it to its final resting place. Plants won’t recover from a virus, and there’s nothing you can do for it. Left in the garden, the sick plant is just a source of disease that could possibly infect other nearby plants.
How to Tell Viruses Apart From Other Pepper Problems
Even for experienced gardeners, it’s not always easy to tell the difference between a viral problem or some other issue. So, don’t jump the gun on assuming a plant has a virus. Both pest attacks and nutrient deficiencies can cause strange yellowing patterns and curled, deformed leaves. Viruses are fairly uncommon in backyard garden peppers, so there’s a good chance it’s something else.
Here are some things to look at:
Viral mosaic tends to start on a random part the plant, often including the newer growth. Yellowing due to the more common nutrient deficiencies (phosphorous, magnesium) affects the lowest leaves first and gradually moves up. While they aren’t always obvious, ringspots and odd patterns within the yellowing are a dead giveaway for viral disease. You won’t see these striking patterns on nutrient-deficient leaves.
Viruses may sometimes cause deformed new growth. But curling, rippling, or twisting leaves is a super common stress response in pepper plants. 99% of the time (not official data!) it’s not virus-related, and the plant will outgrow the problem.
If your peppers have curling or deformed new growth, the first order of business is to check for evidence of aphids or mites. Treat the plants with Neem or insecticidal soap if necessary. If you don’t find bugs, it’s probably just some environmental stress.
Reduce Plant Stress to Prevent Disease
The hands-down best way to defend your pepper patch against any disease is to make sure your plants are happy and healthy, since strong plants are less likely to get sick. Transplant them at the right time (when it’s warm enough out) to prevent stress, and make sure they’re spaced properly. Disease spreads more easily between plants that are crammed too close together.
Pepper plants aren’t super heavy feeders, but they can get deficiencies if your soil is low in certain nutrients, and that makes them more susceptible to problems. Keep an eye out for signs of hungry plants (next section) and feed if necessary.
Nutrient Deficiencies
Peppers aren’t too demanding when it comes to nutrients, but they might be healthier with some fertilizing, depending on your soil situation. Here are some common nutrient deficiencies pepper plants can get and how to spot them:
Nitrogen deficiency- Pepper plants lacking nitrogen will develop pale lower leaves, which will then yellow and drop from the plant. Eventually, the whole plant will start to go pale.
Potassium deficiency- Lack of potassium causes browning or scorching at the leaf edges on lower leaves. The leaves might die back at the tips and will eventually fall off.
Phosphorous deficiency– this deficiency often causes a splotchy yellow mottling on lower pepper plant leaves. The leaves might also develop brownish spots.
Magnesium deficiency- If peppers aren’t getting enough magnesium, the lower leaves will yellow between the veins, while the veins stay green. The affected leaves might also curl up at the edges.
A lot of the time, nitrogen, potassium, and phosphorous deficiencies will show up on young plants soon after transplanting. Cool nights and transplant stress affect the plants’ ability to take in those nutrients, even when they’re available in the soil.
Plants will often outgrow the symptoms of deficiency once the roots get adjusted and established. Some gentle, water-soluble fertilizer such as liquid fish emulsion can help the plants out until the roots get going.
Nitrogen is easily depleted from the soil during the growing season. Peppers (and most other fruiting veggies or leafy greens) will benefit from a top-dressing of an organic, slow-release fertilizer that provides nitrogen early in the season. This will help them establish some healthy green growth before fruiting begins. I like to feed young pepper seedlings with about a teaspoon each of blood meal for some extra nitrogen.
Magnesium deficiency is most common once the plants are fruiting heavily, and it doesn’t really affect production if the symptoms aren’t severe. Watering the plants with a solution of one tablespoon pure Epsom salt (magnesium sulfate) per gallon of water can help correct magnesium deficiency.
If you have well-established pepper plants showing signs of major nutrient deficiencies later in the season, the best thing you can do is get a basic soil test to see what’s going on. You may have a pH issue you need to correct, or your soil may simply be low in certain nutrients.
Peppers, like many vegetables, need a pH between 6.0 and 7.0 for best nutrient intake. It doesn’t have to be perfect, but numbers way outside this range can cause nutrient lockout and deficiency symptoms in the plants. Soil structure problems like poor drainage can also affect nutrient absorption.
With a soil test in hand, you can make plans for some targeted amending for the next season. Correcting soil problems like drainage, pH, and low nutrient levels can take some time, but peppers will usually still produce even if things aren’t perfect. Some water-soluble fertilizer is the best way to deal with severe nutrient deficiencies in the short term, since they’re immediately available to the plants.
Environmental Problems
Despite their hardiness, pepper plants have a reputation for being quite dramatic about it when they’re not happy with the weather. Leaf curl, fruit and flower drop, and stalled growth are all symptoms of environmental stress in peppers.
Cold Stress
Peppers are warm weather crops, native to the tropics and subtropics. Nighttime temperatures below 50 F for more than a few nights will cause young plants to go into “nope” mode. They’ll stop growing and sit there, sometimes for weeks. Any new leaves that do show up may be curled, twisted, or otherwise weird.
The top way to avoid cold stress in your peppers is to wait for ideal weather before planting seedlings. Also, make sure your soil is warm enough. Use a soil thermometer to check, and don’t plant peppers until the soil temp is 60 F or higher.
Sometimes, cold-stressed pepper seedlings are kind of unavoidable. You can watch that extended forecast and think you’re planting at the perfect time. Then, the weather changes its mind once your seedlings are already in the ground. If your pepper seedlings fall victim to cold nights or unexpected cold, rainy days, be patient with them. As long as they didn’t sustain any frost injury, they’ll get over it and start growing in time.
Fertilizing with a diluted water-soluble fertilizer can sometimes help cold-stressed seedlings recover. Just wait until the weather moderates before feeding, since cold plants won’t take in the nutrients anyways. Don’t push the fertilizer too hard, and avoid using anything too strong. Over-fertilizing is more likely to burn stressed plants and create more problems.
Heat Stress
Peppers deal with heat better than they do cold. These tropical plants actually thrive in weather we consider hot. When temperatures push above 90, though, you may see slowed growth, and fruiting plants might take a break from producing peppers. They’ll drop most new flowers and newly forming fruits to conserve water and resources in response to the heat wave.
To reduce the impacts of high heat, make sure your plants are well-mulched to keep the root zone cool and damp. Use a lighter-colored natural material like pine needles or straw to reflect the heat. Don’t fertilize pepper plants during serious heatwaves; forcing new growth while they’re in survival mode can cause further stress.
You can also hang some 30% to 50% shade cloth above the plants, which is more effective than mulch alone for preventing flower and fruit drop. They’ll be okay without shade, though, as long as they have adequate water and the heat isn’t extreme or prolonged. They’ll start producing again once the temperatures come down.
So, what’s extreme heat for peppers, exactly? Temperatures well over 100 F for more than a few days might be enough to damage plants without some shade. Some varieties of pepper are more heat-tolerant than others, and those growing in ground generally handle excessive heat better than potted peppers.
Underwatering
Again, pepper plants aren’t quick to wilt from the heat like some larger-leaved veggies are. If you see your squash or cucumber plants’ leaves hanging like wet rags when it’s 90 + outside, that’s pretty normal. Dramatic wilting in a pepper plant often means the plant needs attention, though.
Pepper leaves naturally droop some and feel soft and floppy, in high heat. But if they’re completely collapsed and shriveled, the plant is probably thirsty. Though pepper plants are tough and can survive periods of water stress, letting them stay thirsty all the time will affect plant health and production. They may start showing signs of nutrient deficiency, and the leaves may take some damage in the form of crispy, brown edges.
Blossom end rot is less common in peppers than tomatoes, but it sometimes shows up due to inconsistent watering. Varieties with larger fruits, like bell pepper and poblano, seem to be more prone to blossom end rot.
Mulching is one of the best ways to prevent water stress in pepper plants. One or two inches of natural mulch will keep the soil evenly damp and drastically cut back on how often you need to water. Also, consider installing a soaker hose or drip tape in your pepper bed. It gets REAL tempting to skimp on watering, when you have to stand out in the July heat with the garden hose sprayer!
Wilting in New Pepper Transplants
Sometimes, newly transplanted pepper seedlings may wilt in the hot sun even when there’s plenty of water available. Earlier this year, I transplanted some Habanero seedlings on what was supposed to be an overcast day. Danged if the sun didn’t come out in full force right after I put them in the ground. They immediately collapsed, so I grabbed some milk crates I had in the barn and put them over the seedlings to filter some of that sun.
When you see wilting pepper transplants, don’t drown them if they’ve already been watered. They’ll most likely pull through if left alone, but providing some temporary shade can prevent any leaf damage.
Overwatering
Signs of overwatering in peppers look a lot like other environmental stress symptoms. Curled leaves, yellowing or discolored bottom leaves, and fruit/flower drop can all happen from overwatering, so it’s hard to identify it as the exact cause.
On your part, the best way to avoid overwatering is to not water wet soil. Wait until the soil feels dry an inch down and give the plants a deep, thorough watering. Once they’re established, pepper plants in the ground will only need extra water during longer dry spells when it’s hot out.
We water our pepper patch once per week when we’re not getting much rain. However, that’s going to vary depending on how hot your weather is and what your soil is like. Pepper plants in pots or containers need water a lot more often than in-ground peppers.
Sometimes, pepper plants end up overwatered due to factors outside of our control (Spring 2025, anyone?). It’s a good idea to prepare your pepper plants for wet weather from the start and plant them in well-drained soil. As long as you prevent root rot, they’ll recover nicely from any leaf curling or nutrient deficiencies they develop from a too-wet spell.
If you’re growing in-ground in heavier soil, consider planting peppers on raised rows or berms to keep the roots out of lingering water.
Anthocyanin: a Natural Pigment Often Mistaken for Disease
Many new pepper growers see their plants’ leaves and stems turning dark purple to black, and they understandably think something’s wrong. Peppers do this a lot, though. It’s a normal pigment they produce in response to high UV light from the sun, similar to my yearly summer farmer’s tan.
Anthocyanin can show up on the stems, stem nodes, leaves, and even the peppers themselves. It doesn’t affect fruit quality or plant health. While it can mean the plants have had to adjust quickly to increased lighting, it’s not usually a sign of major stress.
At the end of the day, peppers are among the most determined of you summer garden plants. We’ve had peppers shredded by slugs, defoliated by bacterial spot and hornworms, and once even blown slap over (stakes and all) when a tornado came through a few miles from our house. All of those plants recovered and produced a good yield.
Even during those unlucky summers when blight gets the tomatoes, the deer get the okra, and the vine borers get the squash, we can still count on making hot sauce in September!
See these posts for more pepper growing tips:
How to Grow a High-Yielding Pepper Patch in Your Garden
Starting Peppers From Seed: The Secrets to Strong Pepper Seedlings
