Early blight of tomato

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 Bligh t Hosts: Tomato, potato, egg plant and other solanum family.

4. Systematic Position Kingdom : Fungi P hy l u m : As c o m y c o ta Class : Dothediomycetes Order : Pleosporales F a m i ly : P l e o sp o raceae 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

9. 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

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

11. Management Cultural control  Clear infected debris from field to reduce inoculum for 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.