Eggplant Verticillium wilt, often referred to as "half yellow and half mad," is one of the three most devastating diseases affecting eggplants. This systemic disease can lead to the entire plant wilting and dying. It is particularly prevalent in long-term vegetable-growing areas where eggplants have been cultivated for many years, leading to a significant drop in field incidence—typically between 20% and 40%.
**First, Onset and Symptoms**
The disease primarily affects the leaves and can occur at any growth stage, but it is most severe during the fruiting period. Symptoms usually appear after the fruit has started to develop. Initially, pale yellow spots form along the veins on the lower leaves, gradually spreading until the entire leaf turns yellow. During the early stages, the leaves may wilt during the day but recover at night or after rain. However, over time, the wilting becomes permanent, the leaves turn brown, curl at the edges, and eventually die off. The disease can spread upward, affecting the whole plant, or just one side of the plant. Infected plants are stunted, with small fruits and brown streaks inside the stems. The base of the stem may rot, and the vascular bundles in the roots and stems turn brown or tan.
**Second, Spread and Infection Methods**
The disease spreads through wind, rain, and agricultural activities. Long-distance transmission is mainly via infected seeds. The pathogen can enter the plant directly through the epidermis or root hairs, or through wounds caused by mechanical damage or insect activity.
**Third, Disease Occurrence Conditions**
1. **Climate Conditions**: The disease thrives in high humidity and temperatures between 20°C and 25°C, with soil temperatures ranging from 22°C to 26°C. High-temperature dry weather reduces the occurrence, and temperatures above 28°C suppress the disease.
2. **Cultivation Practices**: Continuous cropping increases the risk, while crop rotation helps reduce it. Balanced fertilization promotes strong plant growth and resistance, whereas excessive nitrogen application weakens the plants. Low temperatures slow down wound healing, making plants more susceptible. Excessive rainfall, cold irrigation, and low soil temperatures also favor disease development. Poor soil conditions, such as low-lying areas, insufficient organic fertilizer, and improper planting density, further contribute to disease outbreaks.
**Fourth, Prevention and Control Measures**
Combining agricultural practices, such as proper irrigation, adding well-decomposed organic fertilizer, and using plastic mulch, with chemical control methods provides effective management.
1. **Agricultural Control**:
- Rotate crops with non-solanaceous plants like onions or garlic for at least four years.
- Apply 5,000 tons of compost per acre, along with 30 kg of NPK fertilizer as base fertilizer.
- Soak seeds in 50% carbendazim WP diluted 500 times for 2 hours, or soak them in 55°C warm water for 15 minutes.
- Use healthy seedlings with good root systems and avoid using diseased soil.
- Plant on raised beds with mulch, and water on sunny days when the temperature is high to prevent soil cracking.
2. **Chemical Control**:
- Spray 2–2.5 kg of 50% carbendazim WP per acre, or apply it directly into the soil at a depth of 15 cm.
- In the early stages of infection, use 50% carbendazim WP diluted 500 times, or 50% benomyl WP at 0.5 times strength, applying 0.5 liters per plant. Alternatively, use 12.5% synergistic carbendazim WP diluted 200–300 times, applying 100 ml per plant.
3. **Grafting and Root Replacement**:
- Graft eggplant scions onto wild tomato varieties like Yunnan wild tomato or Japanese red eggplant. Using the splicing method can achieve over 95% disease control.
- Ensure the scion is properly developed before grafting, and plant the stock 25 days earlier than the scion. Cut the stock to leave 2 true leaves, and prepare the scion with a wedge-shaped cut. Insert the scion into the stock and secure it with a graft clip. Maintain a temperature of 26°C during the day and over 95% humidity, with shading for 3–4 days. After survival, plant the grafted seedlings in a greenhouse, ensuring the graft union is above ground level to prevent re-infection.
4. **Soil Disinfection or Replacement**:
- After July, spray the greenhouse soil with 10–15 grams of carbendazim or other fungicides, then mix it into the top layer of soil. Cover the area with plastic film and seal the greenhouse to raise the soil temperature to 60–70°C, effectively killing pathogens.
- Soil replacement is more labor-intensive but effective. Remove 30 cm of soil from the greenhouse and replace it with fertile soil that has not grown solanaceous crops for at least three years.
Sunshade And Thermal Insulation Series
Sunshade And Thermal Insulation Series,Black And White Protective Film,Aluminium Foil Double-Sided Sunscreen,Aluminum Foil Woven Fabric Insulation
Changzhou Green Nets Co.,Ltd. , https://www.czglnets.com