Ridge Gourd
Phytophthora blight
Phytophthora capsici
Fungal Disease
Phytophthora capsici
Fungal Disease
Phytophthora capsici
Fungal Disease
Phytophthora capsici
Fungal Disease
Phytophthora capsici
Fungal Disease
Phytophthora blight, caused by Phytophthora capsici, is a serious disease affecting cucumbers at all growth stages and plant parts. The disease thrives under high moisture conditions, making rainfall, overhead irrigation, and soil waterlogging key factors in its development and spread.
Key Details About Phytophthora Blight
1. Symptoms
- Seedlings:
- Damping-off symptoms with watery rot on the hypocotyl or stem near the soil line, leading to plant death.
- Mature Plants:
- Crown rot causing wilting and plant death.
- Vine blight marked by dark olive water-soaked lesions on stems, progressing to brown girdling that collapses foliage.
- Leaves:
- Necrotic spots with chlorotic or olive-green borders; spots merge to cover entire leaves.
- Fruits:
- Water-soaked lesions, especially on fruit surfaces touching soil.
- Lesions expand, causing fruit rot, often covered with white mold and sporangia.
2. Cause
- Oomycete Pathogen: Phytophthora capsici.
3. Disease Cycle and Spread
- Moisture-Driven:
- Free water, high soil moisture, and atmospheric humidity promote mycelial growth, sporangial formation, and zoospore release.
- Rainfall and surface water movement help spread the pathogen across fields.
- Polycyclic Nature:
- Under favorable conditions, P. capsici reinfects crops multiple times in a growing season.
Management Strategies
Cultural Practices:
- Use disease-free seeds and seedlings.
- Avoid over-irrigation and ensure proper field drainage.
- Rotate crops with non-host species to reduce soil inoculum.
Sanitation:
- Remove and destroy infected plant debris promptly.
- Minimize overhead irrigation to reduce pathogen splash.
Chemical Control:
- Apply suitable fungicides targeting Phytophthora capsici.
- Use soil treatments or seed coatings with systemic fungicides.
Preventive Measures:
- Avoid planting in waterlogged fields.
- Use mulch to reduce direct fruit contact with soil.
Phytophthora blight is a destructive polycyclic disease that thrives in high moisture environments. Effective management includes cultural practices, chemical controls, and preventive measures to minimize losses. Proper drainage and sanitation are critical to breaking the disease cycle.
