Anthracnose in Chilli
BHUMI AGRO 30 Sep 2026

How to Identify and Control Anthracnose in Chilli

If your chilli fruits develop black, sunken, circular spots as they start turning red, right when harvest should be paying off, you're likely looking at anthracnose, one of the most economically damaging diseases in Indian chilli farming. If warm‚ rainy weather occurs just before the harvest‚ the fungus quickly destroys the healthy crops‚ as the fungus can attack both green and ripening peppers․ Because of this‚ the disease must be identified and managed early․

This guide covers what causes anthracnose, how to identify it across its different stages, and a complete control plan. For an overview of other common chilli diseases, see our guide to chilli diseases and their management.

Anthracnose in Chilli

What Causes Anthracnose in Chilli? 

Anthracnose in chilli is caused mainly by fungi belonging to the genus Colletotrichum, including Colletotrichum capsici and related species. This fungus can infect fruits, leaves, stems, flowers and seedlings.

  • Infected seed: The fungus can survive on the surface or inside the seed and infect seedlings post-germination․

  • Diseased crop residues: Infected fruits‚ leaves‚ stems and dead twigs can carry the fungus between cropping seasons․

  • Contaminated Soil: Spores/structures may survive in the soil, and any contact with soil can infect fruits․

  • Infected seedlings and volunteer plants: Infected seedlings from nurseries‚ weeds, and volunteer chilli plants can transfer the disease to a new field․

  • Other host crops: Related crops such as tomato and brinjal may act as reservoir hosts near chilli fields․


How Anthracnose Spreads in Chilli

  • Rain splash and runoff water. 

  • Insects moving between infected and healthy fruits. 

  • Contaminated tools, hand and farm equipment.

  • Wind-driven rain

  • Insects moving between infected and healthy fruits. 

  • Overhead irrigation

  • Infected planting material

  • Contact between infected crop debris and fruit

  • Harvesting and handling activities 

TNAU identifies seed transmission as an important primary source, while airborne spores, rain and insects contribute to secondary spread.


How To Identify Anthracnose

Anthracnose is usually identified by sunken lesions on chilli fruits, often with concentric rings and tiny black fungal structures. It may also cause leaf spots, stem lesions, flower shedding and dieback.

Symptoms on Fruits

  • Small, circular, water-soaked or yellowish spots appear first.

  • Spots become brown, black or grey and gradually enlarge.

  • Lesions are usually sunken and may become oval or elongated along the length of the fruit.

  • Concentric rings may form around the lesion․

  • Tiny black dots (acervuli) may form on the rings.

  • Pink, orange or salmon-coloured spore masses may be visible in wet conditions.

Symptoms on Leaves 

  • Small brown to black circular or irregular spots․

  • Several spots merge into large dead patches.

  • greyish-white‚ or cream-colored necrotic areas in some cases.

  • Severe infection results in yellowing and premature leaf drop․

Symptoms on Flowers and Seedlings 

  • dark brown‚ elongated lesions.

  • Drying starts from the shoot tip‚ moving from front to back․

  • Terminal branches can die suddenly․

  • Greyish or dead tissue containing tiny black fruiting bodies.

This shoot-killing phase is commonly called dieback.


The Latent Infection Problem

One of the most important things to know about anthracnose‚ is that a Colletotrichum species will remain latent (hidden) on its host‚ and fruit remains green‚ with no signs of infection‚ until the time of ripening and reddening‚ when the characteristic sunken lesions will then appear․

By the time you notice fruit rot in ripening chillies‚ the infection may have occurred weeks earlier during flowering or initial fruit-set․ As a result‚ spraying preventatively when flowering and early fruit-set are taking place is recommended․ 


How To Control Anthracnose

1. Cultural Control 

  • Use certified clean seeds. Always use disease-tested‚ certified seeds․ Do not save seed from fields that have had anthracnose․

  • Practice crop rotation. Follow a 3-4 year crop rotation with non-host crops. It breaks up the cycle of fungal buildup.

  • Sanitize your field. Remove and burn infected plant debris‚ twigs and fallen fruits․

  • Switch to drip irrigation. Avoid overhead sprinkler irrigation‚ which creates a rain-splash effect that keeps foliage wet․

  • Ensure proper field drainage. Plant on raised beds to prevent waterlogging. Maintain wider row spacing (e.g., 60 cm × 45 cm)

2. Seed Treatment (Pre-Planting) 

Treating seeds eliminates seed-borne pathogens before germination: 

Type Treatment Method Dosage
Biological Trichoderma viride or T. harzianum 10 g / kg of seed
Bacterial Bio-agent Pseudomonas fluorescens 10 g / kg of seed
Chemical Captan 50% WP OR Thiram 75% WP 2–3 g / kg of seed
Hot Water Treatment Soaking seeds in hot water at 52°C (125°F) 30 minutes (dries before sowing)


3. Biological Control 

Biocontrol agents form protective barriers and produce natural substances that fight harmful microbes.

  • Foliar Bio-Fungicides: spray Trichoderma harzianum or Pseudomonas fluorescens at 5-10 g/L every 10-14 days during wet or high-humidity periods. 

  • Botanical Sprays: Apply Neem Seed Kernel Extract (NSKE 5%) or cold-pressed Neem Oil (3 mL/L with a mild spreader sticker) to inhibit spore germination on leaf surfaces. 

4. Chemical Fungicide Control

Chemical sprays are essential during high-risk weather (high humidity or when temperature is 28-30°C) or during outbreaks․

  • Preventive (Contact Fungicides): Applications at flower bud initiation and early fruit setting before symptoms develop․

  • Curative (Systemic Fungicides): Apply at the first sign of small fruit lesions or die-back․ 

Mode of Action Active Ingredient Recommended Dose Primary Use Case
Contact / Protective Mancozeb 75% WP 2.5 g / L of water Preventive spray before rain/humidity spikes
Contact / Protective Copper Oxychloride 50% WP 3.0 g / L of water Preventive/general fungal protection
Contact / Protective Chlorothalonil 75% WP 2.0 g / L of water High contact barrier against spore landing
Systemic (Curative) Azoxystrobin 23% SC 1.0 mL / L of water Early fruit setting & active infection control
Systemic (Curative) Difenoconazole 25% EC 0.5 mL / L of water Broad-spectrum curative spray
Systemic Combination Tebuconazole 50% + Trifloxystrobin 25% WG 0.7 g / L of water Heavy infection outbreak control


Fungicide Resistance Warning: Do not use systemic fungicides with the same FRAC (Fungicide Resistance Action Committee) code group continuously back to back; rotate these with alternates that have different FRAC code groups (e․g․ Strobilurins such as Azoxystrobin alternate with Triazoles such as Difenoconazole or contact fungicides such as Mancozeb) every 10 to 14 days․


Anthracnose vs Leaf Curl - Two Very Different Problems 

If you have read our Chilli Leaf Curl Disease Guide, the contrast here is worth noticing. Leaf curl is viral, transmitted by whitefly and cannot be treated with any kind of fungicide. Management is entirely about vector control and prevention. 

Anthracnose is fungal and will respond to the application of a fungicide at the right time․Confusing the two, or treating one as if it were the other, wastes both money and the treatment window that actually matters. Correct identification always comes first. 


Conclusion

Don't let a microscopic fungus burn through your harvest before your chilli even reaches the market. By breaking the spread early through field sanitization and proactive protection, you can keep the heat in your peppers and the rot out of your fields. 













Frequently Asked Questions

Control combines cultural practices, disease-free seed, field drainage, crop rotation, and removing infected debris, with preventive fungicide application timed to flowering and early fruit development, since the fungus can infect fruit before any visible symptoms appear.

Fungicides combining a strobilurin (like Azoxystrobin) with a triazole (like Difenoconazole) provide both preventive and curative action against Colletotrichum species through two different mechanisms, making them effective against anthracnose when applied preventively starting before flowering.

Fungicides containing Azoxystrobin combined with Difenoconazole, or traditional protectants like captan applied preventively from before flowering onward, are effective against anthracnose-causing Colletotrichum species when timed correctly and applied before visible symptoms appear.

No. Left untreated, anthracnose continues to spread under favorable humid conditions and can cause severe fruit rot, twig dieback, and yield loss. Because the fungus can infect fruit without visible symptoms until ripening, waiting to see if it resolves on its own typically means the infection has already progressed significantly by the time it's noticed.

Effective control combines using certified disease-free seed with seed treatment, ensuring good field drainage, following a 3–4 year crop rotation with non-host crops, removing infected plant debris after harvest, and applying preventive fungicide sprays timed to flowering and early fruit development rather than waiting for visible fruit rot.