In this PPT you will come to know about the EARLY BLIGHT OF TOMATO disease which causes a severe damage and yield loss in tomato plant.And also you will come to about their management and their resistant varieties.

1. PAT 301-DISEASE OF FIELD AND
HORTICULTURAL CROPS AND THEIR
MANAGEMENT-1

2. EARLY BLIGHT OF TOMATO

3. Disease Name:
Tomato Early blight
Pathogen Name:
Alternaria solani
Common Name:
Early Blight
Hosts:
Tomato, potato, egg plant and other solanum family.

4. Systematic Position
Kingdom : Fungi
Phylum : Ascomycota
Class : Dothediomycetes
Order : Pleosporales
Family : Pleosporaceae
Genus : Alternaria
Species : A. solani

5. Occurrence
History and Diversity
Early blight is caused by Alternaria solani (Ell. & Mart.)
L.R. Jones and Grout.
A. solani is problematic in tomato production areas east of
the Rocky Mountains and is generally not an issue in the
less humid Pacific or inter-mountain regions

6. Pathogen description
The mycelium which is septate and branched, hyaline in the
beginning and later becomes darker in colour.
The conidia are 12-20 × 120-296 µm and are found singly
or in chains of two.
Conidiophores are short and produces an obclavate or
muriform shaped conidia with horizontal and vertical
septation and it is pointed at distal end.

7. Symptoms:
Foliar symptoms of A. solani generally occur on the oldest
leaves and start as small lesions that are brown to black in
color.
These leaf spots resemble concentric rings a distinguishing
characteristic of the pathogen.
Both the area around the leaf spot and the entire leaf may
become yellow or chlorotic.
Stem lesions are dark, slightly sunken and concentric in shape.
 Fruit spots are similar in appearance to those on leaves –
brown with dark concentric circles. Mature lesions are
typically covered by a black, velvety mass of fungal spores

8. Leaf lesion of Alternaria solani
Stem lesion of Alternaria solani

10. Spread of disease
Mode of survival:
The conidia and the mycelium in the soil or in the debris of the affected
plants can remain viable for more than 17 months.
Mode of spread:
Primary spread by air borne conidia Secondary spread by
infected plant debris

11. Epidemiology:
Dry warm weather with intermittent rain.
Poor vigor.
Temperature: 25-30°C.
Poorly manured crop.

12. Management
Cultural control
Clear infected debris from field to reduce inoculumfor the next year.
Rotate to a non-Solanaceous crop for at least three years.
Removal and destruction of infected plant debris should be done
because the spores lying in the soil are the primary source of infection
Chemical control
Very early spraying with Zineb or captan 0.2% and repeating it for every
15 – 20 days gives effective control.