Fungal disease of chilli and their eco friendly management in NE States of India

RC Shakywar, Rakesh Kr Dubey, P Raja, Vikash Singh *

Chilli (Capsicum annum L.) also called red pepper is an important cash crop in India and North Eastern Region of India. It is grown for its pungent fruit both green and ripe fruits and used to impart pungency to the food. As a condiment, it has become indispensable in every Indian house. It is used medicinally, in chutney and pickles.

India has become world’s largest producer and exporter of chilli by exporting to Canada, Germany, Malaysia, Saudi Arabia, Singapore, UK, USA and many other countries across the world. India contributes 25 per cent of the world’s total production of chilli.

Some of the hottest chilli such as Bhut Jolokia vernacular meaning (Bhut = ghost, Jolokia = chilli) Bih Jolokia (meaning poison chilli) and Naga Jolokia (named after the once ferocious Naga warrior tribe of North East India). This cultivar is being grown and consumed in different States of the region like Assam, Nagaland, Manipur and Mizoram from time immemorial.

So hot is the chilli that local people handle and consume it with respect. Any normal person who dares to eat a whole Bhut Jolokia would almost certainly require hospital treatment. Indian chillies have been dominating International chilli market. In India, chilli is mainly grown in States of Andhra Pradesh, Maharashtra, Karnataka, Gujarat, Tamil Nadu and Orissa.

ECONOMIC IMPORTANCE:

The Chilli anthracnose was first reported in India, Coimbatore of Madras Presidency in 1913 by Sydow. The disease has been identified in all the chilli producing regions of world and has become a serious constraint to chilli production.

SYMPTOMATOLOGY:

This disease appears as small circular spots that coalesce to form large elliptical spots on fruits and leaves. However, that different species cause diseases of various parts of the chilli plant. While, in this region and a part of country the disease has been reported in three phases namely seedlings blight or damping off, leaf spot, die-black or anthracnose or fruit rot.

CAUSAL AGENT/CAUSAL ORGANISM/PATHOGEN:

The different species of Colletotrichum namely C. capsica, C. gloeosporoids and C. acutatum are known to anthracnose in chilli in India and North Eastern region of India. The pathogen has a wide range of hosts including cereals, legumes, vegetables, perennial crops and tree fruits.

ETIOLOGY:

Initial infection by Colletotrichum species involves a series of processes including the attachment of conidia to plant surfaces, germination of conidia, production of adhesive appressoria, penetration of plant epidermis, growth and colonization of plant tissue and production of acervuli and sporulation.

Anthracnose is mainly a problem on mature fruits, causing both pre and post-harvest fruit decay resulting severe economic losses. Appressoria that formed on immature fruits may remain quiescent until the fruits mature or ripen.

EPIDEMIOLOGY:

Colletotrichum species can survive in and on seeds as acervuli and micro sclerotia. Survival of mycelia and stomata in colonized chilli seeds had also been reported. It has been shown that the pathogen readily colonized the seed coat and peripheral layers of the endosperm even in moderately colonized seeds.

Heavily colonized seeds had abundant inter and intracellular mycelia and acervuli in the seed coat endosperm and embryo, showing disintegration of parenchymatous layers of the seed coat and depletion of food material in endosperm and embryo. Environmental factors play a major role in the development of disease epidemics.

The relationships among rainfall intensity, duration and crop geometry and dispersal of inoculum possibly lead to different levels of disease severity. The effects of temperature often interact with other factors, such as leaf surface wetness, humidity, light or competitive micro-biota.

The duration of the surface wetness, however, appears to have the most direct influence on the germination, infection and growth of the pathogen on the host. Generally infection occurs during warm, wet weather. Temperatures around 270C and high relative humidity (a mean of 80%) are optimum for anthracnose disease development.

ECO-FRIENDLY MANAGEMENT OF FUNGAL DISEASE OF CHILLI:

1. Eradication of infected plant parts from main field, collect and burn it immediately.
2. Use of neem seed cake @50g/m2 in nursery.
3. Seed treatment with bio-control agent such as Trichoderma harzianum (native isolate) @4g kg-1 seed.
4. Soil application with neem seed kernel extract @4% 1-1 before sowing in main field.
5. Foliar application (during first appearance of disease symptom) of Nemarin @ 3ml 1-1 or neem oil @ 0.05% 1-1.