Causes of Dead Seedlings in Sichuan Pepper and the Latest Control Methods
Sichuan pepper is an important economic crop in China. With the progress of the Grain for Green Project, the planting area of Sichuan pepper is also increasing year by year, and the phenomenon of dead seedlings in Sichuan pepper is also quite serious, severely restricting the development of the Sichuan pepper industry. So what are the causes of dead seedlings in Sichuan pepper? How should they be controlled? Let's take a look together.
1. Damage from underground pests
During seedling raising, underground pests are serious, such as white grubs, mole crickets, wireworms and other underground pests. They mainly damage the roots of seedlings, with adults and nymphs biting and harming the roots of Sichuan pepper seedlings, causing missing seedlings and broken rows.
Control method: During the seedling raising period, the nursery should first be leveled and then deep-plowed and aged to prevent damage from underground pests such as white grubs, mole crickets, and wireworms. When preparing the land, insecticide can be broadcast per mu, then shallow-plowed and harrowed evenly, so that the soil is loose and the ground is level.
2. Damping-off
Damping-off, also known as dead seedling disease, occurs after the seedlings emerge. The pathogen often invades through the root collar and then spreads to the young roots and young stems, causing the seedlings to lodge and quickly wither and die. After the lignified stems of the seedlings are damaged, although the seedlings do not lodge, damping-off symptoms appear, and because the lignified stems of the seedlings have stronger resistance, the probability of damage is reduced.
Control method: Before cultivation, a good nursery site should be selected. Soil is the main source of infection for the pathogen. Generally, plots that have long been used for growing vegetables accumulate more pathogens, so such land is not suitable for selection as nursery land. At the same time, fungicide should be applied when preparing the land to reduce the pathogen base and lower the possibility of disease occurrence.
3. Root rot from waterlogging
In nursery land with a high groundwater table, poor drainage, and heavy clay soil, root rot often occurs, mainly caused by root oxygen deprivation and suffocation after water accumulation. At first, the leaves turn yellow and the leaf margins scorch, and then the plant slowly withers and dies. If the dead plant is pulled out, a large number of rotten roots will be found, accompanied by a sour, rotten smell.
Control method: For nursery land with a high groundwater table and poor drainage, the seedling raising technique of deep furrows and high beds can be adopted to control water accumulation and prevent waterlogging. For nursery land with heavy clay soil, decomposed farmyard manure can be used to enhance soil permeability and improve soil structure.
4. Root rot from chemical fertilizer
When seedlings lack nitrogen, growth is slow, vigor is weak, resistance to external conditions is low, and disease is very likely to occur. But when a large amount of nitrogen fertilizer is applied, the coordinated relationship between carbon and nitrogen metabolism in the plant is disrupted, and the seedlings remain green and grow excessively. Moreover, the cuticle is relatively thin, the sclerenchyma is underdeveloped, and the plant is soft and sprawling. After the root system absorbs excessive chemical fertilizer, the cortex at the root collar turns black, and the xylem under the skin also turns dark brown. In severe cases, the root system rots and dies.
Control method: For root rot caused by excessive nitrogen fertilizer, nitrogen fertilizer should be appropriately reduced, and attention should be paid to the ratio of nitrogen, phosphorus, and potassium, so as to avoid excessive green growth and leggy growth of seedlings and improve disease resistance.
The above is an introduction to the causes of dead seedlings in Sichuan pepper and the control methods. We hope it can help you. If you want to learn more related knowledge, please follow us.