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early and late leaf spot of groundnut
1. COLLEGE OF AGRICULTURAL TECHNOLOGY
Affiliated to Tamil Nadu Agricultural University, Coimbatore
Kullapuram, Via Vaigai dam, Theni-625 562
EARLY AND LATE LEAF SPOT OF GROUNDNUT
STUDENT COURSE TEACHER
PREETHI. V Dr. S. PARTHASARATHY
ID. No. 2016021034 Asst. Prof., (Plant Pathology)
2. SIGNIFICANCE
• Groundnut (Arachis hypogaea) is one of the important
oilseeds and food crops of the world as it provides an
inexpensive source of high quality dietary protein and
edible oil.
• Early and late leaf spots, commonly called as
tikka disease in groundnut - economically important
foliar fungal diseases.
4. GLOBAL DISTRIBUTION
• Leaf spot causes significant yield loss, and can be
found wherever Groundnut is grown. This includes
areas such as USA, Australia, Fiji, Solomon Islands
and Tonga.
• In India states such as Gujarat, Andhra Pradesh,
Karnataka, Tamil Nadu and Maharashtra.
• It is estimated that late leaf spot reduces yields by
50% or more in Pacific island countries.
7. EARLY LEAF SPOT: Cercospora arachidicola (Hori)
Sexual stage (Mycosphaerella arachidis)
Scientific classification
• Kingdom : Fungi
• Phylum : Ascomycota
• Class : Dothideomycetes
• Subclass : Dothideomycetidae
• Order : Capnodiales
• Family : Mycosphaerellaceae
• Genus : Cercospora
• Species : C. arachidicola
Fungi-Cercospora arachidicola
8. LATE LEAF SPOT:
Passalora personata (Berk. & M.A. Curtis)
Sexual stage (Mycosphaerella berkeleyi)
Scientific classification
• Kingdom : Fungi
• Phylum : Ascomycota
• Class : Dothideomycetes
• Subclass : Dothideomycetidae
• Order : Capnodiales
• Family : Mycosphaerellaceae
• Genus : Passalora
• Species : P. personata
9. PATHOGEN CHARACTER
Cercospora arachidicola
• The pathogen is intercellular, the mycelium consists
of both external and internal hyphae and do not
produce haustoria and become intracellular when host
cells die.
• The fungus produces abundant sporulation on the
upper surface of the leaves.
10. • Asexual reproduction takes place by means of long,
usually hyaline, multiseptate conidia.
• Conidiophores are olivaceous brown or yellowish
brown in colour, unbranched and arise in clusters.
• Conidia are pale yellow, obclavate.
13. Passalora personata
• The fungus produces internal
and intercellular mycelium with the production of
haustoria.
• The conidiophores are long, arise in clusters and
olive brown in colour.
• The conidia are cylindrical or obclavate.
15. EPIDEMIOLOGY
FAVOURABLE CONDITIONS
• Prolonged high relative humidity for 3 days.
• Low temperature (20°C) with dew on leaf surface.
• Heavy doses of nitrogen and phosphorus fertilizers.
• Deficiency of magnesium in soil.
16. MODE OF SURVIVAL
• The pathogen survives for a long period in the
infected plant debris through conidia, dormant
mycelium in soil.
17. PRIMARY AND SECONDARY SPREAD
• The primary infection is by ascospores or conidia
from infected plant debris or infected seeds.
• The secondary spread is by wind blown conidia. Rain
splash also helps in the spread of conidia.
18. MANAGEMENT
• Remove and destroy the infected plant debris.
• Keep weeds under control.
• Grow moderately resistant varieties like ALR 1.
• Varietal screening was carried out with different 16
varieties, among them variety GJG-32 and TG-37A
were found resistant and highly susceptible,
respectively.
19. • Use of resistant varieties is an ideal, simple and
cheapest method for the control of plant disease.
• CHEMICAL CONTROL
• Treat the seeds with Thiram at 2g/kg.
• Spray Carbendazim (Bavistin) 500g or Mancozeb
(Indofil M -45) 2 kg/ha.
20. REFERENCES
Gupta, V.K., Paul, Y.S., and Sharma Sathish, K. 2012. Fungi
and Plant Diseases. Kalyani publishers, New Delhi.
Rangaswami, G., and Mahadevan, A. 1999. Disease of Crop
Plants in India. PHI learning private limited.
http://cec.nic.in/wpresources/module/BOTANY/PaperI/33/c
ontent/downloads/file2.pdf
http://oar.icrisat.org/821/1/RA_00080.pdf