SYMPTOMS, PATHOGEN, MANAGEMENT

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram(Po), Via Vaigai dam , Theni -625 562
AA
VERTICILLIUM WILT OF COTTON
STUDENT COURSE TEACHER
SIREESHA .N Dr. PARTHASARATHY .S
ID.No.2016021042 Asst.Prof.,(Plant Pathology)

2. SIGNIFICANCE
 The world uses more cotton than any other fiber.
 Cotton is a leading cash crop in the U.S
 The production of each year’s crop involves the
purchase of more than $5.3 billion worth of supplies
and services.

3.  Major disease in USA and USSR
 First reported in 1968- on hirsutum cottons in
coimbatore, India
 The disease usually appears in November -December

4. ECONOMIC LOSSES:
• It causes about 10-15 percent loss on average.
• During 1980’s caused severe damage in Southern
High plains and Texas.

5. DISTRIBUTION:
World wide India
 Europe(wide spread) Tamil Nadu
 South Africa Maharastra
 Brazil Karnataka
 Canada Rajasthan

6. SYMPTOMS:
 The symptoms are seen when the crop is in squares
and bolls.
 The first symptoms can be seen as bronzing of veins.
 It is followed by interveinal chlorosis and yellowing
of leaves.
 Finally the leaves begin to dry, giving a scorched
appearance.
 The drying of the leaf margins and areas between
veins, which gives a Tiger stripe or Tiger claw
appearance.

7.  Infected stem and roots, when split open, show a
pinkish discolouration of the woody tissue.
 The infected leaf also shows brown spots at the end
of the petioles.
 The affected plants may bear a few smaller bolls with
immature lint.

13. SYSTEMATIC POSITION:
Kingdom :Fungi
Division :Ascomycota
Class :Deuteromycetes
Subclass :Hypocreomycetidae
Order :Hypocreales
Family :Plectosphaerellaceae
Genus :Verticillium
Species :V.dahliae (Kleb.1913)
V.albo-atrum (Reinke &Berthhold, 1872)

14. PATHOGEN:
Verticillium dahliae, Verticillium alboatrum
 The fungus produces hyaline, septate mycelium and
two types of spores.
 The conidia are single celled, hyaline, spherical to
oval, borne singly on verticillate conidiophores.
 The micro sclerotia are globose to oblong.

16. MODE OF SURVIVAL:
 The fungus can survive in the infected plant debris
and in soils as micro sclerotia upto 14 years.
 The seeds also carry the micro sclerotia and conidia
in the fuzz.
 PRIMARY SPREAD:
o Micro sclerotia or conidia in the soil.
 SECONDARY SPREAD:
o Contact of diseased roots to healthy ones .
o Through dissemination of infected plant parts
through irrigation water and other implements.

17. FAVOURABLE CONDITIONS:
 Low temperature of 15-20‫ﹾ‬ C.
 Low lying and ill-drained soils.
 Heavy soils with alkaline reaction.
 Heavy doses of nitrogenous fertilizers.

18. MANAGEMENT:
CULTURAL METHODS:
 Treat the delinted seeds with Carboxin or
Carbendazim at 2g/kg.
 Isolation of affected plants.
 Follow crop rotation by growing paddy or lucerne or
chrysanthemum or barley.
 Avoid late season irrigation and soil solarisation
effectively controls wilt.
 Growing disease resistant varieties like Sujatha,
Suvin and CBS 156 and tolerant variety like MCU 5
WT.

19. CHEMICAL METHODS:
 Systemic fungicides like Vitavax 0.4% or
Organomercurials.
 Spot drench with 0.05g/l benomyl or carbendazim
500mg/l.
 Fumigate soil with chemicals such as methyl bromide
and chloropicrin.

20. REFERENCES:
• http://eagri.org/eagri50/PATH272/lecture13/002.html
• http://www.padil.gov.au/pests-and-
diseases/pest/main/136633
• Saha ,L.R., 2002.Hand book of plant diseases,Kalyani
publishers,New Delhi.