Detailed Explanation of the Causes of Prickly Ash Seedling Death and Control Methods
Prickly ash (Zanthoxylum bungeanum) is an important economic crop in China. With the implementation of the Grain for Green Project, the planting area of prickly ash has been increasing year by year. However, the phenomenon of prickly ash seedling death is also quite serious, severely restricting the development of the prickly ash industry. So what are the causes of prickly ash seedling death? How should it be controlled? Let's take a look together.
1. Damage from underground pests
During seedling raising, underground pests are severe, such as white grubs, mole crickets, and wireworms. These underground pests mainly damage the roots of seedlings, with adults and nymphs biting and feeding on the roots of prickly ash seedlings, causing missing seedlings and broken rows.
Control method: During the seedling raising period, the nursery should first be leveled and then deeply plowed and aged. To prevent damage from underground pests such as white grubs, mole crickets, and wireworms, insecticides can be broadcast per mu during land preparation, followed by shallow plowing and raking to make the soil loose and the ground level.
2. Damping-off disease
Damping-off disease, also known as seedling death, 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, the seedlings do not lodge but show damping-off symptoms. In addition, as the seedling stems become lignified, their resistance increases and the probability of damage decreases.
Control method: Before cultivation, a good nursery site should be selected. Soil is the main source of pathogen infection. Generally, plots that have been used for vegetable cultivation for a long time accumulate more pathogens, so such land is not suitable for selection as a nursery site. At the same time, fungicides should be broadcast during land preparation to reduce the pathogen base and lower the possibility of disease occurrence.
3. Root rot from waterlogging
In nursery sites 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, leaves turn yellow and leaf margins scorch, after which the plant gradually withers and dies. When the dead plant is pulled out, a large number of rotted roots will be found, accompanied by a sour, rotten smell.
Control method: For nursery sites 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 sites with heavy clay soil, the method of using decomposed farmyard manure can be adopted to enhance soil permeability and improve soil structure.
4. Root rot from chemical fertilizers
When seedlings lack nitrogen, they grow slowly, become weak, and have weak resistance to external conditions, making them highly susceptible to disease. 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 become excessively vegetative and leggy. In addition, the cuticle layer is relatively thin, the sclerenchyma tissue is underdeveloped, and the plant is soft and lush. After the root system absorbs excessive fertilizer, the cortex at the root collar turns black, and the subepidermal xylem 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 to prevent seedlings from becoming excessively vegetative and leggy and to improve disease resistance.
The above is an introduction to the causes of prickly ash seedling death and control methods. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.