Postharvest Diseases of Chilli & Their Management

Chilli (Capsicum frutescens) is an important spice crop and India is one of the leading producers and exporters of Chilli in the world.  Chilli is widely used around the world in food as a spice both in fresh and dried form which adds flavour to the meal by creating a spicy pungent taste. The chemical components of the Chilli may vary considerably depending on the location of cultivation and postharvest treatments.

Chilli contains polyphenol compounds such as capsaicin capsorubin, zeaxanthin and cryptoxanthin are responsible for color in Capsicum species that accounts for its characteristic aroma and therapeutic properties. Postharvest losses in Chilli are estimated to be 25-35%. Due to post-harvest losses, farmers lose both in quality and quantity of the Chilli.  Knowing the symptoms and management methods will be highly useful to Chilli growers. With this view, this article is prepared to minimize the post-harvest losses due to diseases.

BACTERIAL SOFT ROT

Pathogen: Pectobacterium sp

Symptoms

• The fleshy fruit peduncle is highly susceptible and is frequently the initial point of infection.

• Both ripe and green fruit may be

• Initially, the lesions on the fruit are light to dark-colored, water-soaked and somewhat

• The affected areas expand very rapidly, particularly under high temperatures, and tissues lose their texture.

• In later stages, bacterial ooze may develop from affected areas and secondary organisms follow, often invading the rotted tissue.

• Post-harvest softening of stem-end of fruit.

• The affected fruit hangs from the plant like a water-filled

Management

• Use chlorinated wash water to reduce populations of soft rot bacteria and to reduce the risk of infection during

• Allow fruit to dry

• During packing and storage the fruit should be kept clean and maintained in a cool, dry

• Seed treatment – 1% sodium hypochlorite for 30 sec, then rinse with clean water

• Avoid planting  pepper  crops  following  crops of  potato  or  cabbage

• Rotate instead with crops of bean, corn and soybean

ALTERNARIA ROT

Pathogen: Alternaria solani

Symptoms

• The fungus is reported to enter wounds (sun scald or punctures). Dusty black spores on fruit spots are characteristic.

• In most instances, this disease follows blossom-end rot, but it also follows injuries, chilling, and other decays.

• On the fruit, large greenish-brown to brown lesions covered, with grayish-brown mold are produced.

• Similar lesions on the lower-part of the fruit are characteristic of Alternaria rot following blossom-end

• The larger lesions may show alternating light and dark-brown concentric

• Shipping peppers under standard refrigeration will check the development of this rot, but when the fruit is removed from refrigeration the decay will advance rapidly at moderate to warm temperatures.

Management

• The effectiveness of storage dry heat treatment and hot water dip in reducing storage rot of capsicum  caused by Alternaria alternata.

• Treatment with hot air at 38˚C for 48-72 h or hot water at 50˚C to 53˚C for 2 to 3 minutes, resulted in reduction in the pathogenicity and development of these pathogens in inoculate peppers.

• Fortnightly spraying of Bordeaux mixture 1.0 % or Copper oxy chloride 0.3 % or Difolatan 0.3 % or Mancozeb 0.2%

ANTHRACNOSE

Pathogen: Colletotrichum capsici

Symptoms

• Ripe fruits turning red are affected.

• Small, black, circular spot appears on the fruit skin.

• Badly diseased fruits turn straw colour or pale white colour, lose their pungency.

• Diseased cut open fruits - lower surface of the skin is covered with minute, elevated sclerotia observed.

• Advanced stage - seeds covered by a mat of fungal hyphae, turn rusty.

Management

• Use disease free seeds.

• Seed treatment - Thiram 2 kg/ha or Zineb 2.5 kg/ha.

• Three sprayings with captan 0.2 %1^st spraying - just before flowering, 2^nd at the time of fruit formation, 3^rd  -  fortnight interval after second spraying.

GRAY MOULD

Pathogen: Botrytis cinerea

Symptom

• Brownish spots develop near the soil line or cotyledons

• Water-soaked  lesions on leaves & stems darken and collapse

• Water-soaked spots that rapidly expand into large yellowish-green or grayish-brown, irregular lesions that are soft and spongy in texture.

• Velvet-like fungus mycelium and spores are produced on the lesion surface under cool, humid conditions

Management

•  

  Field sanitation - remove and burn decaying infected plant parts

• Space seedlings and transplants to allow for free flow of air through the crop

• Treatment with hot air at 38°C for h or hot water at 50°Cto 53°C for 2 to 3 min

LATE BLIGHT

Pathogen: Phytophthora capsici

• Infected leaf tissue - wilted, light green, or gray-green, later becoming tan to white and scalded in appearance with moisture, leaf spots have a water-soaked border.

• Fruit rots - irregular in shape and olive green or light green with water-soaked borders.

• Rots expand rapidly and fruits can be completely diseased and desiccated, causing the formation of "mummified" fruits.

• Infected seeds are brown and shriveled.

Management

• Rotation with non-susceptible crops will reduce the amount of Phytophthora capsici surviving in soil.

• Fresh, clean seeds should be planted in new potting mix to establish healthy transplants.

• Monitor seedlings as well as the field and remove diseased plants as soon as they occur.

REFERENCES

1. Dasgupta, M. K. and Mandal, N. C. 1989. Post-harvest Pathology of Perishables. Oxford & IBH Publishing co. Pvt Ltd, New Delhi, Bombay, Calcutta, pp. 623.

2. Dennis, C. 1983. Soft fruits. In: Post-Harvest Pathology of Fruits and Vegetables (ed.) Dennis, 23-42, Academic Press, London.

3. Dennis, C. 1987. Fungi. In: Post-harvest physiology of Vegetables (ed.) J. Weichmann, 377-411, Marcell Dekker, Inc., New York.

4. Eckert, J.W. and Sommer, N.F. 1967. Control of diseases of fruits and vegetables by postharvest Annual Review of Phytopathology, 5: 391-392.

5. Logan, C. 1983. Potatoes. In: Post-Harvest Pathology of Fruits and Vegetables (ed.) Dennis,             pp. 179-217, Academic Press, London. 

6. Prabakar,2021 Postharvest Diseases of Peri8shables and Management. Daya publishing.pp 49-54.

Authors

K.Prabakar, 1, G.Karthikeyan 2 and  L. Pugalendhi 3 and S.Vanitha 4

1. Professor, Plant Pathology, TNAU, Coimbatore

2. Professor and Head, Department of Plant Pathology, TNAU, Coimbatore

3. Professor and Head, Department of Plant Pathology, TNAU, Coimbatore

4. Professor, Plant Pathology, TNAU, Coimbatore