Fungal Wilt of Cotton Diseases of Field Crops and Thier Management

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
Affiliated to Tamil Nadu Agricultural University, Coimbatore
Kullapuram, Via Vaigai dam, Theni-625 562
VERTICILLIUM WILT OF COTTON
STUDENT COURSE TEACHER
Miss. SIVAMONICA .B Dr. PARTHASARATHY. S
ID. No. 2015021117 Asst. Prof., (Plant Pathology)

2. OCCURRENCE:
• Major disease in USA and USSR.
• First reported in 1968 – on hirsutum cottons in
Coimbatore, India.
• The disease usually appears in November - December

3. DISTRIBUTION:
Worldwide India
Europe (widespread) Tamil Nadu
South Africa Maharastra
Brazil Karnataka
Canada Rajasthan

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

5. SYMPTOMS:
• Mottling of leaves, interveinal chlorosis, scorching of
leaves.
• Irregular yellowing at margin & vein causes drying,
known as “Tiger Stripe symptom”.
• Necrosis of leaves from lower to upper with heavy
defoliation.
• Pinkish to pinkish brown discoloration of vascular
system of stem and roots.
• Generally it occurs after first flower.

6. ©Nyngan oberver
Tiger Stripe symptom in leaves

7. http://www.padil.gov.au/pests-and-
diseases/pest/main/136633
Tiger Stripe symptom in leaves

8. Pinkish Brown discoloration
©publication W 403, Tyson Raper

9. Pinkish Brown discoloration
© PaDil

10. PATHOGEN:
Verticillium dahliae, V. alboatrum
• Conidia - single celled, hyaline, spherical to oval,
singly on verticillate conidiophore.
• It produces microsclerotia, globose to oblong in
shape.
©cals.ncsu.edu

11. https://www.apsnet.org/edcenter/intropp/lessons/fung
i/ascomycetes/Pages/VerticilliumWilt.aspx

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

13. LIFECYCLE
LIFE CYCLE:
©aps.net.org

14. MODE OF SPREAD:
• Mostly by root contact in soil.
• Also carried in the fuzz of the seeds.
• Microsclerotia remains in soil for a longer period of
more than 15 yrs.
• Resting bodies can withstand freeze, heat, thaw and
remains for a longer period.

15. FAVORABLE CONDITIONS:
• Atmospheric temperature of 15-20ºC, cool wet
weather.
• Low lying and ill drained heavy soils with alkaline
reaction.
• Nov – Dec during crop in square and bolls or almost
three months after sowing.

16. IDM:
CULTURAL METHODS:
• Isolation of affected plants.
• Practise crop rotation with corn, lucerne, barley, sorghum,
rice.
• Avoid late season irrigation and soil solarisation
effectively controls wilt.
• Tolerant varities like Sujatha, CBS-151, Acala and Pima
varieties.
• Using acid delinted seeds @ 100ml/kg of seeds.

17. CHEMICAL METHODS:
• Systemic fungicides like Vitavax 0.4% or organomercurials.
• Soil drenching with Benomyl 0.05 percent at triweekly interval.
• Foliar application of Benomyl 0.05 percent (Benlate, Agrocit).
• Fumigate soil with chemicals such as methyl bromide and/or
chloropicrin
• Other chemicals that are used against Verticillium spp. are the
antifungal antibiotic aureofungin, the fungicides benomyl, captan,
carbendazim, thiram, azoxystrobin and trifloxystrobin and the plant
defence activator acibenzolar-S-methyl