Cercospora Leaf Spot is a common fungal disease that affects eggplants(Brinjal), also known as aubergines. The disease is caused by the fungus Cercospora melongenae. It is characterized by the appearance of small, circular spots on the plant leaves, which then enlarge and become irregularly shaped. These spots are usually surrounded by a yellow halo and can appear on the leaf’s upper and lower surfaces.
If left untreated, the spots may merge, leading to leaf curling and defoliation. Although Cercospora Leaf Spot does not infect the fruit directly, it can lead to reduced yields due to lower productivity of the plants. The fungus can live in plant debris and soil for up to a year, making it a persistent problem in areas where the disease is prevalent.
Cercospora Leaf Spot Management in Eggplant
The causal organism of Cercospora Leaf Spot Disease
- The causal organism of Cercospora Leaf Spot Disease is a plant-pathogenic fungus called Cercospora melongenae.
- This fungus can survive in plant debris and soil for at least one year and is commonly spread by wind and water, including rain and irrigation.
- Infected tools and persons can also disperse it. The fungus typically infects the lower, older leaves of plants and moves up the stem to younger foliage.
The Disease cycle of Cercospora Leaf Spot Disease
- Under moderate to warm temperatures (between 78 to 90ºF) and in the presence of free moisture, the conidia germinate and infect the plant tissue. Once the fungus infects the plant, it begins to grow and reproduce, causing the characteristic symptoms of the disease.
- During warm and wet weather, new cycles of infection and sporulation can occur every seven to 10 days. The infected plant tissues produce new conidia that are spread to nearby healthy tissues or other plants by wind or splashing water, continuing the disease cycle.
Causes/Conditions favorable for Cercospora Leaf Spot Disease spread in the field.
- Heavy soils and low-lying areas that retain soil moisture for long periods can create conditions that favor the growth of the fungus.
- Air-borne spores (conidia) disseminated by wind, rain splashes, tools, implements, and field workers, can easily spread the fungus from infected to healthy plants.
- Free water on the plant surface is required for the conidia to germinate and infect the plant tissue.
- Favorable temperatures between 26-32°C promote the rapid development of the disease, with new infections occurring every 7-10 days.
- High relative humidity and continuous plant wetness create a conducive environment for the growth and spread of the fungus.