Introduction to Tomato Diseases
- Overview of diseases affecting tomatoes.
- Importance of disease management in agriculture.
- Focus on early blight, late blight, and bacterial diseases.
Causal Organisms of Tomato Diseases
- Early Blight: Alternaria solani
- Late Blight: Phytophthora infestans
- Bacterial Wilt: Ralstonia solanacearum
- Leaf Curl Virus: Tomato leaf curl virus
Early Blight Symptoms
- Dark spots on older leaves, stems, and fruits.
- Yield losses can reach 79% in severe cases.
- Weakens plants, reducing fruit set.
Favorable Conditions for Early Blight
- Temperatures between 15 to 27°C.
- High humidity (>90%) and rainy weather.
- Weak plants from June-July sowing are more susceptible.
Management of Early Blight
- Use pathogen-free seeds and remove infected debris.
- Water in the morning to minimize leaf wetness.
- Implement crop rotation with non-Solanaceous crops.
Late Blight Overview
- Caused by Phytophthora infestans.
- Can infect leaves, stems, and fruits rapidly.
- Historically linked to the Irish potato famine.
Symptoms of Late Blight
- Dark brown blotches on leaves with green-gray edges.
- Fruits develop dark, mushy spots.
- High humidity leads to white fungal growth.
Favorable Conditions for Late Blight
- High humidity (>90%) and low temperatures (10-25°C).
- Cloudy weather with rainfall enhances spread.
- Soil-borne spread through oospores.
Management of Late Blight
- Destroy infected potato piles before planting.
- Crop rotation with cereals to prevent recurrence.
- Use prophylactic sprays of copper fungicides.