Root rot in chickpeas is a disease primarily caused by the soil-borne pathogen Phytophthora medicaginis, leading to the decay and destruction of the plant's roots.
Here's a more detailed breakdown:
Causes of Chickpea Root Rot
- Phytophthora medicaginis: This is the main culprit, thriving in wet and waterlogged conditions. It is a soil- and water-borne pathogen.
- Other potential pathogens: While Phytophthora medicaginis is most common, other fungi can also contribute to root rot in chickpeas.
Disease Cycle
- Survival: Phytophthora medicaginis survives in the soil between chickpea crops as oospores and chlamydospores (resting spores).
- Germination: When a susceptible chickpea crop is planted and soil conditions are favorable (wet), these spores germinate.
- Infection: Germinated spores produce mycelium (fungal threads) and zoospores (motile spores). Zoospores swim through the soil water to infect chickpea roots.
- Disease Development: The pathogen destroys root tissue, hindering the plant's ability to absorb water and nutrients.
- Spread: The pathogen can spread through infected soil, water runoff, and farm equipment.
Symptoms of Root Rot in Chickpeas
- Yellowing and wilting: Above-ground symptoms often start with yellowing and wilting of the leaves, even when the soil appears moist.
- Stunted growth: Infected plants exhibit reduced growth compared to healthy plants.
- Root discoloration: The roots will show dark brown or black discoloration and decay.
- Lesions on the stem: Brown lesions may appear at the base of the stem near the soil line.
- Plant death: In severe cases, the entire plant can die.
Conditions Favoring Root Rot
- Wet soil: Saturated or poorly drained soil is ideal for Phytophthora medicaginis development and zoospore movement.
- High humidity: Humid conditions promote disease spread.
- Warm temperatures: Moderate to warm temperatures are conducive to pathogen growth.
- Poor soil structure: Compacted soil can exacerbate drainage problems, increasing the risk of root rot.
Management Strategies for Chickpea Root Rot
- Crop rotation: Rotating chickpeas with non-host crops (e.g., cereals) can reduce pathogen levels in the soil.
- Improved drainage: Ensure proper soil drainage to avoid waterlogging.
- Resistant varieties: Planting chickpea varieties with resistance to Phytophthora medicaginis is an effective control measure.
- Seed treatments: Using fungicide seed treatments can protect seedlings from early infection.
- Fungicides: Applying fungicides to the soil or foliage can help control the disease, but efficacy may vary.
- Soil solarization: Covering the soil with clear plastic during the hot summer months can kill pathogens.
- Avoid over-irrigation: Careful irrigation management prevents waterlogged conditions.
Root rot in chickpeas, caused by Phytophthora medicaginis, is a significant threat that farmers can manage with proper planning and preventative measures.
