Damping-off is a common problem in producing eggplant, also known as Brinjal, which refers to the death of seedlings before or after emergence, particularly under damp conditions. This phenomenon is a significant concern for eggplant growers, as the plants are typically transplanted into the field.
Any loss of seedlings can result in decreased yield and economic losses. Damping-off is more prevalent in the transplant nursery, particularly under cooler conditions. While eggplant seedlings are no longer susceptible to Pythium or Rhizoctonia infection once they reach the 2-3 leaf stage, they can still be infected by Phytophthora at any stage.
Damping Off Management in Eggplant
The causal organism of Damping Off Disease
- Damping-off disease is caused by several species of fungi, including Pythium spp., Phytophthora spp., Fusarium spp., and Rhizoctonia spp.
- These fungi can survive in soil, plant debris, or infected seeds and can be easily spread by water, wind, tools, and workers.
- Once the fungus infects the seed or seedling, it can cause the rotting of the stem, roots, and cotyledons, leading to the plant’s wilting, collapse, and death.
The Disease cycle of Damping Off Disease
- Presence of the pathogen: The pathogen that causes the damping-off disease is present in the soil, either as dormant spores or actively growing hyphae.
- Germination of spores: When favorable environmental conditions, such as high moisture and warm temperatures, the spores germinate and produce hyphae.
- Infection of seedlings: The hyphae grow into the roots of the seedlings, killing plant tissue as they grow. This can occur within minutes of infection by certain pathogens such as Pythium.
- Spread of disease: The pathogen can spread within the soil, either by growing through the soil or moving around by soil-dwelling organisms such as nematodes.
- Production of survival structures: Some pathogens can produce sexual spores in the roots or soil resistant to adverse environmental conditions, allowing them to survive in a dormant state for months or years.
Causes/Conditions favorable for Damping Off Disease spread in the Eggplant field.
- Heavy soils: Heavy soils with poor drainage provide a favorable environment for the growth and spread of damping-off pathogens.
- Low pH: Acidic soils with a pH below 6.0 can promote damping-off development.
- Heavy seeding resulting in dense planting: Overcrowding of plants due to heavy seeding can lead to increased humidity and reduced air circulation, which creates a favorable environment for damping-off.
- Excessive soil moisture: Overwatering and poorly drained soils can create conditions that favor the growth and spread of damping-off pathogens.
- Low light and presence of weeds: Low light and weed growth can reduce air circulation and increase humidity, creating a favorable environment for damping off.
Symptoms of Damping Off Disease in Eggplant
- Damping-off disease in eggplant can cause various symptoms in young seedlings, including a failure of seeds to germinate, rotting and discoloration of young stems near the soil line, wilting, collapse, and death of young seedlings.
- The affected seedlings may have discolored and rotting roots, and in high-humidity situations, white, fluffy growth of the causal pathogen may develop on infected tissues.
- The disease typically affects new plantings and can occur in just a few seedlings or maybe more extensive, resulting in poor stand establishment and the need to replant.
- Eggplant seedlings beyond the initial stage of development can also be affected by stem lesions, which can girdle and kill the plant.
- The damping