Disease of cotton

1. BOLL ROT OF COTTON
COLLEGE OF AGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po),ViaVaigai Dam, Theni-625 562
STUDENT
Miss. SOUNDARI A
ID. No. 2015021121
COURSE TEACHER
Dr. PARTHASARATHY S
Asst. Professor (Plant Pathology)

2. CAUSAL ORGANISM
• Fusarium moniliforme
• Colletotrichum capsici
• Aspergillus niger
• Aspergillus flavus
• Rhizophus nigricans
• Nematospora nagpuria
• Botryodiploidia spp. ©mississippi-crops.com

3. LOCAL NAME – Kai alugal ( Tamil name)
HISTORY:
• According to Hillocks (1992) – The pathogen causing boll
rot divided into 3 groups. They are introduced by insects and
penetrate through the wounds.
• According to Belot and Zambiasi (2007)- there are many
pathogens cause boll rot such as A.flavus, B.pumilus,
Colletotrichum spp., Fusarium spp.

4. • According to Ranney et al. (1971) – classified four factors that cause
infection long wet period, long period with RH 75%, low light
intensity, long over cast period and high temperature.
DISTRIBUTION:
• Brazil, India and US.
• Aspergillus flavus - Coachella, Palo Verde and Imperial valleys.
• Aspergillus niger - California.
• Fusarium moniliforme – Iran, Sahiwal, Punjab, Pakistan, Multan.
• Rhizophus nigricans – Iran.

5. ECONOMIC SIGNIFICANCE:
The incidence of boll rots is generally less than 5 percent,
although under optimum conditions upto 30 per cent of
bolls can be affected. Boll rots cause losses by reducing
yields, by staining and reducing the strength of the lint,
and by infecting the seed.
HISTORY SIGNIFICANCE:
Each year the California cotton crop suffers quality
reduction and yield losses estimated at 3.55% to 4.0% due
to fungus boll-rotting organisms.

6. SYMPTOMS:
• Brown or black dots covering entire bolls.
• Rotting may be internal or external.
• Bolls do not open and fall maturely.
©mississippi-crops.com ©kisansuvidha.com

7. Fusarium moniliforme symptoms:
Turn light brown. Pink mass of spores are
present over the surface of the unopened boll.
©invasive.org

8. Colletotrichum capsici symptom:
• Small water soaked, circular, reddish brown
depressed spots appear on the bolls.
• The lint is stained to yellow or brown, becomes
a solid brittle mass of fibre.
©infonet-biovision.org ©eplantdiseases.blogspot.com

9. SYMPTOMS
Aspergillus niger Rhizophus nigricans
©pestnet.org ©kisansuvidha.com

10. Pathogen:
Anamorph – Fusarium moniliforme
Author : Sheld
Teleomorph – Gibberella fujikuroi var.monilformis
Author : (Wineland) Kuhlman.
Aspergillus:
Anamorph – Aspergillus niger
Teleomorph – Eurotium niger

11. Colletotrichum:
Anamorph: Colletotrichum capsici
Author : Syd
Teleomorph : Glomerella cingulata

12. SYSTEMATIC POSITION:
Kingdom: Fungi
Phylum: Ascomycota
Subphylum: Pezizomycotina
Class: Sordariomycetes
Subclass: Hypocreomycetidae
Order: Hypocreales
Family: Nectriaceae
Genus: Fusarium
Species: Fusarium moniliforme (J.Sheld)

13. SYSTEMATIC POSITION
Kingdom : Fungi
Phylum : Ascomycota
Subphylum: Pezizomycotina
Class: Sordariomycetes
Order: Glomerellales
Family: Glomerellaceae
Genus: Colletotrichum
Species: C. capsici (Syd.) E.J. Butler & Bisby,
(1931)

14. SYSTEMATIC POSITION
Kingdom: Fungi
Phylum: Ascomycota
Class: Eurotiomycetes
Order: Eurotiales
Family: Trichocomaceae
Genus: Aspergillus
Species: A. niger (Tiegh)

15. SYSTEMATIC POSITION
Kingdom: Fungi
Phylum: Ascomycota
Class: Eurotiomycetes
Order: Eurotiales
Family: Trichocomaceae
Genus: Aspergillus
Species: A. flavus (Link)

16. SYSTEMATIC POSITION
Kingdom: Fungi
Division: Zygomycota
Class: Mucormycotina
Order: Mucorales
Family: Mucoraceae
Genus: Rhizophus
Species: Rhizophus nigricans (Ehrenb)

17. Fusarium moniliforme
Characteristics:
1.The hyphae is brown, pink or purple at maturity. Asexual spores
namely, microconidia, macroconidia and chlamydospores.
2. Microconidia are very small,
round to oval in shape.
3. Macroconidia are large, multicellular
usually 2-4 celled and sickle shaped
in morphology.
4. Chlamydospores are thick walled,
oval or rounded.
©biologydiscussion.com

18. MODE OF SPREAD:
• Soil borne and sometimes airborne conidia.
• The infection of cotton bolls developed after
peneteration by the fungi either through
feeding and oviposition wounds made by Red
cotton bug (Dysdercus cingulatus) , Boll
weevil, Cotton bollworm, Lygus bug.

19. Colletotrichum capsici
Characteristics:
Conidiophores
1.The pathogen forms large number of
acervuil on the infected parts.
2.The conidiophores are slightly curved,
short, and club shaped.
3.The conidia are hyaline and falcate,
borne single on the conidiophores.
4.Numerous black coloured and thick
walled setae are also produced in ©biologydiscussion.com
acervulus .

20. Mode of spread:
1.Soil borne and seed borne.
2.Sometimes through airborne conidia.
3.The pathogen also perpeptuates on the rotten
bolls and other plant debris in the soil.
4.The pathogen also survives in the weed
hosts viz., Aristolachia bractiata and
Hibiscus diversifolius.

21. Aspergillus niger
Characteristics:
• Asexual - Conidiophore
colour is black.
• Sexual- Ascospores
are globose and bright
red or yellow in colour.
A. flavus
• Conidiophore colour ©pininterest.com
is green.

22. Lifecycle:
©biologydiscussion.com

23. Mode of spread
• A. flavus produced aflotoxin.
• Insect – lygus bug, stink bug, pink bollworm
transmit the diseases.
• Soil and wind borne.

24. Rhizophus nigricans:
Characteristics
Asexual – chlamydospore.
Sexual – zygospore and sporongiosphore.
©pininterest.com

25. Lifecycle:
©biologydiscussion.com

26. Mode of spread:
• Cotton bollworm and pink boll worm wounds
created.

27. Favourable condition:
• Heavy rainfall during the square and boll formation
stage, punctures caused by the insects, especially Red
cotton bug Dysdercus cingulatus.
• Close spacing.
• Excessive nitrogen
application.
©invasive.org

28. IDM:
Cultural methods:
• Adopt optimum spacing.
• Apply the recommended doses of fertilizers.
• Remove and burn the infected plant debris and
bolls in the soil.
• Rogue out the reservoir weed hosts.

29. Chemical methods
• Treat the delinted seeds with Carbendazim or
Carboxin of Thiram or Captan at 2g/kg.
• Spray Fenvalerate 75g a.i./ha + Copper
oxychloride 2.5kg or Carbendazim 1kg or
Mancozeb 2 kg/ha from 45th day at 15 days
interval. Two or three sprays are necessary.