Eggplant Sclerotinia Symptoms and Prevention Methods

There are many kinds of eggplant diseases, so today I will introduce to you how to prevent and treat eggplant sclerotinia disease?

pathogen

Ascomycota fungi - Sclerotinia sclerotiorum (Lib.) De Bary.

Eggplant Sclerotinia

symptom

The disease can occur throughout the entire growth period. The disease begins at the base of the stem during the seedling stage, and the diseased part initially appears as light brown water stains.

When the humidity is high, white cotton-like mycelium grows, which is soft and rotten, without odor. It turns grayish white after drying. The mycelium gathers into sclerotia, the diseased part shrinks, and the eggplant seedlings wither and die. The disease can occur in all parts of the plant during the adult stage, starting from the base of the main stem or 5 to 20 cm from the side branches. It initially appears as light brown water-soaked spots, which are slightly sunken and gradually turn grayish white. When the humidity is high, white flocculent hyphae also grow. The cortex rots, and black sclerotia are formed on the surface and pith of the diseased stem. After drying, the pith is hollow, the surface of the diseased part is easily broken, and the fibers are exposed in a hemp-like manner, causing the plant to die; the affected leaves also appear water-soaked at first, and then turn into brown circular spots, sometimes with ring patterns, and white hyphae grow on the diseased surface. After drying, the spots are easily broken; the flower buds and flowers are affected, and water-soaked wet rot appears, eventually leading to shedding; the fruit stalks are affected, causing the fruit to fall off; water-soaked spots initially appear on the affected end or sunny side of the fruit, which then turn brown and rot, slightly sunken, and white mycelium grows on the spot surface, and then forms sclerotia.

Occurrence characteristics

The pathogen mainly overwinters or oversummers in the soil and mixed in seeds as sclerotia. When the environmental conditions are suitable, the sclerotia germinate to produce ascospores, which are spread by air currents and penetrate the cuticle of the host directly, causing the initial infection. The pathogen re-infects multiple times through contact between diseased and healthy plants, aggravating the damage. Sclerotia are suitable for survival in dry soil and can survive for more than 3 years, and can survive for about 1 month when immersed in water.

The pathogen prefers a warm and humid environment. The most suitable conditions for disease occurrence are a temperature of 20-25°C and a relative humidity of more than 85%. The peak period of disease occurrence in Zhejiang and the middle and lower reaches of the Yangtze River is from February to June in spring. The most suitable growth period for disease occurrence is from the mature stage to the middle and late stages of fruiting.

The disease is more serious in fields with low-lying terrain, poor drainage, over-dense planting, poor ventilation and light transmission in the greenhouse, and continuous cropping for many years. The disease is more serious in years with heavy rain in early spring or during the rainy season.

Prevention and treatment methods

(1) Covering the ground with plastic film when growing eggplant in a plastic shed can prevent the ascocarps from emerging from the soil and reduce the source of bacteria.

(2) Treat the soil with chemicals. Use 4-5 kg ​​of 50% carbendazim wettable powder per mu, mix it with dry soil and spread it on the surface of the bed, then rake it into the soil. This can reduce the source of initial infection.

(3) Pay attention to ventilation to reduce the humidity in the greenhouse. When a cold wave hits, pay attention to heating to prevent the plants from freezing and inducing disease.

(4) If diseased plants are found, remove them immediately and take them outside the greenhouse for destruction.

(5) Chemical control: After the first diseased plants are found in the field, they should be rotated or used alternately, once every 10 to 15 days, for 3 to 4 times in a row. In addition, smoke or dust methods can also be used in protected areas. For specific methods, see Cucumber Sclerotinia.