Look for lesions on ripe and overripe pepper fruit. They’re black or brown, sunken, and wet. Anthracnose may continue spreading after harvest once you’ve brought your peppers inside. Watch for rotten spots, and dispose of any peppers that exhibit these symptoms.

Anthracnose thrives in warm temperatures and lots of water, either from rain or irrigation. Use well-draining soil and water only once your soil is dry. Space at least one foot apart to encourage proper airflow. If you have space, rotate where you plant peppers every two to three years to keep anthracnose from overwintering.

Copper fungicide slows anthracnose infections, preventing them from spreading to healthy plant tissue. Apply doses according to the package’s directions. Bolster your pepper’s immunity by ensuring there is proper fertility present in the soil. Mulch can help too.

Root rot symptoms include:

• Slow or stunted growth
• Yellow leaves
• Wilting
• Root death

Root rot organisms thrive in overly wet soils. Prevent infection by using free-draining soil and watering regularly once the soil dries. Avoid watering soil that is already wet—excess moisture may pool, creating perfect conditions for root rot growth. Peppers appreciate moist, but not soggy soil. They also benefit from a mycorrhizal treatment; use beneficial mycorrhizae at planting to give your crop added protection from root rot.

Once root rot reaches a certain point, it is impossible to cure. Remove yellow leaves and dead stems to prevent more damage. If one of your plants has the infection, remove it to limit root rot’s spread. Dispose of your sick pepper away from your garden.

You may be able to save a plant that has root rot by removing it from the garden and quarantining it. Inspect the root system, and see if there are still a substantial amount of white, healthy roots. If there are, remove the dead, brown, and rotten roots with scissors or shears. Then replant in a sterile container with clean soil.

Watch for peppers with brown, discolored spots on them. Spots spread over peppers near the end where the blossom was. These spots spread inside and out, leading to mushy, rotten peppers. Salvage infected peppers by removing rotten spots when you harvest.

This disease occurs when the crop has issues taking up calcium, typically due to drought stress. The lack of consistent moisture makes transfer of calcium difficult for soil microbes. Ensure you’re using a regular watering schedule that maintains moist but not soggy soil.

If you’re watering regularly and your peppers still have rotten spots, they may need an application of fertilizer. Use an organic fertilizer for fruiting plants, applying a half dose weekly for two to three weeks. Espoma Organic Liquid Tomato Food is perfect for this. Watch new peppers as they form to see whether blossom-end rot subsides.

All powdery mildew strains make patches of fuzzy gray-white growth on pepper leaves. The mildew spreads to other leaves, eventually infecting surrounding crops. This disease occurs commonly in warm climates with high overnight humidity. Overhead irrigation causes moisture to sit on the foliage, leading to high ambient humidity.

Powdery mildew spreads in warm locations with high humidity around peppers. This occurs with crowded plants, low airflow, and shade. Prevent the disease by spacing plants correctly under full sun. Plant strong, disease-resistant varieties, mulching their soil well. In climates where powdery mildew is prevalent, avoid overhead sprinklers or irrigators—they cause higher humidity, which leads to increased fungal spore germination.

Prevent small outbreaks by cutting off infected leaves, then dispose of them. If powdery mildew keeps growing, use one of these organic methods sparingly. Alternate them to avoid harboring treatment-resistant strains of this fungus:

• Sulfur fungicide
• Potassium bicarbonate fungicide
• Milk spray
• Bacillus subtilis fungicide

Note that these aren’t always effective at reducing the presence of the disease, but instead are useful for preventing its spread.

Spot these viruses growing on leaves and fruits—look for rings of yellow or brown mottled spots. Infected plants may have stunted growth, and dead portions. They may exhibit leaf curl and suddenly die after exhibiting some of these symptoms. The mosaic virus prevents crops from taking in nutrients.

Encourage good airflow, by spacing out your crops a foot or more apart. Pull weeds in your garden to prevent mosaic virus from growing on neighboring foliage. Tobacco mosaic virus can also spread from tobacco products, so keep them and their smoke away from the garden. Smokers should wash their hands before re-entering the garden. Plant mosaic virus resistant varieties, especially if you’ve had issues with the disease in the past. The ‘Sweet Bell Blend’ is tobacco mosaic virus resistant, and the fruits are deliciously sweet!

Using milk sprays on structures around the garden works surprisingly well to limit tobacco mosaic virus. There are no known cures for cucumber mosaic virus. Prevent this disease from growing by removing infected plants. Dispose of them away from your garden to keep these diseases from spreading.

Verticillium wilt presents itself as yellowing, dead leaves, and stems. Symptoms start at the edges of the plant and move inward. With time, entire plants wilt to the ground. Watch out for brown stems, leaves, or fruits. If one pepper wilts while one next to it has yellowing leaves, it has likely spread.

Keep verticillium wilt away with proper cultural conditions like these:

• Establish a garden plot with proper soil fertility
• Water and care for your peppers consistently
• Rotate with crops of broccoli, sorghum, corn, safflower, or barley every two years
• Ensure you’re using sterile tools

There is no known treatment for verticillium wilt. Soil solarization may work, although it also kills plenty of beneficial soil bacteria, leaving it open for other diseases. Remove all infected plants at the time of infection, and use prevention methods each year—this builds resilient soil for your crops.

This blight presents itself as dying or browning stems, as well as dying roots. It’s hard seeing the roots below ground, however, above-ground wilting is easily viewable. Look for infections during hot weather between 75-90°F (24-32°C) when soils are moist and warm simultaneously.

Keep infections at bay by avoiding overhead irrigation. Sprinklers, however convenient, encourage splashing this oomycete from soils onto your crop foliage. This helps spread phytophthora blight from its cozy home in the soil onto your pepper’s leaves or fruits. Use drip irrigation, or slowly saturate vegetable beds with a trickling hose for an hour.

Also, provide excellent drainage for your peppers, and sanitize your tools between prunings. Do not plant in areas where the fungus has been present if possible. Grow disease-resistant varieties.

Remove any infected plants, and watch for further infections. Dispose of any infected plant parts, and do not compost them. The prevention methods above will discourage this disease from returning.

Look for spots on leaves. They’ll be yellow or brown at first in tiny patches. Over time spots spread throughout the leaves. They’ll yellow and fall en masse. Also, look for malformed fruits around harvest time.

Keep bacterial leaf spots away by disinfecting tools in between uses. The goal with bacterial leaf spot is to stop its reproduction and prevent further spread. Clean up crop debris at season’s end. Compost healthy plant material, but dispose of infected peppers away from your garden. As always, an application or two of compost or mulch helps by encouraging healthy organisms to battle bacterial leaf spots.

If only part of your pepper’s leaves have spots, cut them off and throw them far away from your vegetables. Try limiting bacterial leaf spots from spreading onto new plants. Research shows that copper sprays limit bacterial leaf spot from growing in severe infestations, but they must be used in conjunction with other systemic chemicals to be effective.

Southern blight makes lesions on lower leaves and stems in the early stages of infection. With time, the crowns, fruit, and top leaves rot. Mycelia grow out of infected pepper material—they look like white, fuzzy roots. Watch for tiny brown or white bumps that look like tiny mushrooms; they’re structures that house spores in the soil.

Keep this fungus away by promoting these cultural techniques:

• Inspect new plants and soil for southern blight
• Space one foot apart
• Use compost or mulch on your soil
• Remove infected plants
• Rotate peppers with barley, sorghum, corn, or wheat every two to three years

Once a pepper plant has southern blight there is nothing that can cure it. Remove the infected plant, as well as the surrounding soil. Soil solarization is one organic method for large southern blight growths. Apply black plastic onto your soil during the summer season—hot temperatures and direct sunlight kill the fungus. Remove the plastic in autumn, and by spring you’ll be able to grow healthy peppers again.