Anthracnose of cotton is caused by 2 species of Colletotrichum which are seed borne in nature. This Cotton disease has worldwide distribution. In India , it was 1st reported from Bihar in 1918 by Butler. The Average estimated yield loss ranges from 1-3% to as high as 80-90%. The major symptoms are seen on the leaves. The leaves develops water soaked circular , Sunken , reddish brown lesions . When the condition is dry the tissue in the center of the lesions drys & fall down .It can be control by spraying Bordeaux mixture on seedlings .

1. COURSE NAME – DISEASES OF FIELD &
HORTICULTURAL CROPS & THEIR
MANAGEMENT (PP-365)
TOPIC – ANTHRACNOSE OF COTTON
Submitted to : Prados Kumar Jena
(Asst. Prof. of Plant Pathology)
Submitted by : Baishali Mohanta
Roll No. 2119
B.Sc. Ag. 6th Sem
MITS INSTITUTE OF PROFESSIONAL STUDIES

2. CONTENT
• Introduction
• Taxonomy
• Symptoms
• Etiology
• Epidemiology
• Disease cycle
• Management

3. INTRODUCTION
• Anthracnose of cotton is caused by 2 species of colletotrichum which
are seed borne in nature.
• This cotton disease has worldwide distribution.
• In india it was 1st reported from Bihar in 1918 by Butler.
• It annually Causes losses which range from slight to as high as 80-
90% of the crop with an average estimated at from 1-3%.

4. TAXONOMY
• Causal organisms – Colletotrichum capsici
• Sexual stage - Glomerella gossypii
• Kingdom – fungi
• Division – Eumycota
• Sub-division – Deuteromycotina
• Class – Coelomycetes
• Order – Melanconiales
• Family – Melanconiaceae
• Genus - Colletotrichum

5. SYMPTOMS
• All the above ground parts of the plant are infected & plant
can be infected at any stage of their growth.
• The cotyledons & primary leaves show small reddish circular
spots.
• The lesions at the collar region of the stem resulting death of
the young seedlings.
• In mature plants, the fungus attack the stem resulting in
splitting & shredding of bark.

6. SYMPTOMS
• The symptoms are prominent on bolls as water soaked ,
circular ,sunken & reddish brown lesions developed.
• The lesions later turns black with red margins.
• The lint become yellow to brown , rot & transformed
into brittle fibres.
• Seed are also infected , shrivelled, discolored & brown
in colour.
• Affected bolls are smaller in size & boll cease to grow &
brust & dry up prematurely.

7. Circular red spots on leaves Infected stem

8. Leisons on seedlings Lint becomes yellow & brittle

9. ETIOLOGY
• Asexual fruiting body – Acervulli
• Sexual fruiting body - Perithecia
• Mycelium – Septate, inter & intra cellular , branched, hyaline
• Acervulli – cushion shaped , black coloured
• Setae - Straight, unbranched , Tapering at the apex , Brown – Black
at the base & light brown at the tip.
• Conidiophores – slightly curved , short & club shaped.
• Conidia - falcate shaped , Hyaline , thin walled , single celled &
Posses oil globule
• Resting spores - Chlamydospores Setae

10. Acervulus Conidia

11. Colony of Colletotrichum capsici on PDA
Acervulus

12. EPIDEMIOLOGY
• Temperature – 28 - 32°C
• Humidity. - 95%
• Prolonged rainfall at the time of boll formation increase
the disease incidences.
• Close planting should be avoided.
• If there are rains during the 1st 3 weeks after the
emergence of the plants, seedling blight is very common

13. LIFE STYLE OF
COLLETOTRICHUM
1. Biotrophic lifestyle
2. Entophytic lifestyle
3. Necrotic lifestyle
4. Quiescent lifestyle

14. DISEASE CYCLE
• 1° infection source – seed borne
• 2° infection source – Air borne conidia
• Alternate host – Aristolochia bractiata & Hibiscus diversifolius
• Pathogen survives as dormant mycelium in the seed or as conidia
on the surface of seed for about a year.
• The pathogen also perpetuate on the rotten boll & other plant
debris in the soil.

15. DISEASE CYCLE
Disease cycle

16. DISEASE CYCLE
• Species of colletotrichum have asexual & sexual morph in their disease.
• Penetration & colonization

18. HOST – PATHOGEN INTERACTION
1. The deposition of conidia on the plant surface
2. Attachment of conidia to those surface
3. Germination of conida
4. Production of appressoria
5. Penetration of the epidermis
6. Growth & colonization of plant tissues
7. Production of Acervulli & sporulation

19. MANAGEMENT
• Cultural Management
• Deep summer ploughing
• Crop rotation with non host
• Use of disease free seed
• Collect & destroy all infected plant parts.
• Biological control
• Application of trichoderma & Pseudomonas fluorescence

20. MANAGEMENT
• Chemical control
• Seed treatment with captan or Thiram @3-4g/kg .
• Spray the seedlings with Bordeaux mixture .
• Spray 3 times with Carbendazim @ 0.1% just before flowering , at fruit
formation stage & 15 days after second spray.
• Disinfect all garden tools with one part bleach & 4 part water.
• Spray Copper fungicide such as Blitox @ 2kg/ha in 1000 lit of water to
check seedling blight & boll rot.
• Dusting with calcium cyanmide@15kg/acre reduce humidity.

21. Common name Trade name Dose
Thiram Thiride 0.15-0.2% foliar spray
Captan Captan 50 W 0.2 – 0.3% seed
treatment
Copper oxychloride Blitox -50 0.3-0.5% foliar spray
Carbendazim Bavistin 50WP 0.1% foliar spray

23. Thank you