Causes and control methods of dead seedlings of stevia rebaudiana

Stevia is a perennial herb whose leaves contain as much as 6% Mel 12% sugar. It is regarded as one of the three major sugar sources in the world and is now grown all over the world. In the process of cutting and raising seedlings of stevia, there are many dead seedlings, caused by physiological diseases and infectious diseases. Let's take a look at it together with Xiaobian.

1. Physiological diseases

Physiological diseases are mainly related to soil, such as soil pH value is too high or too low, improper application of seedling bed base fertilizer may cause a large area of dead seedlings, this disease is not rooted, does not sprout, stem blackening, and then leaves black, dead seedlings. In addition, the herbicides with long residual time and sensitive to stevia were applied in the previous crop, which led to the poisoning and death of stevia after cutting. this symptom was mainly characterized by blackening of leaves and blackening of young stems. In addition, the management after cutting is also very important, if high temperature and high humidity, it will also cause a large area of dead seedlings.

2. Infectious diseases

There are mainly three kinds of infectious diseases that cause the dead seedlings of stevia. One is a kind of bacterial blight, which is a fungal disease and the main disease in the process of raising stevia seedlings, which occurs in the general seedling bed and is relatively rare in the field. The main symptom is that the stem base of the seedling leaves the city with water-stained yellow disease spot, expands, overflows and shrinks, showing a dark brown dry death. The second is Sclerotinia sclerotiorum, which is also a fungal disease, which usually occurs in the seedling bed from February to April, when the disease occurs, waterlogged irregular disease spots appear at the base of individual seedlings, and gradually spread to the upper and lower parts, resulting in the plant wilting showing dark brown death, and rapidly spread to Zizhou, sometimes hundreds of seedlings died in the whole seedling bed. The third is Fusarium wilt, which is a systematic infection disease in the production of stevia, which mainly occurs on the seedling bed of melon crops and cotton planting plots, which is easy to be induced in rainy days and the most serious in long rain.

3. Prevention and control methods

For the prevention and control of physiological diseases, mainly to improve the change of seedling environment, the first is not to use toxic soil to raise seedlings; the second is not to use melons and cotton stubble to raise stevia seedlings to prevent the occurrence of soil-borne diseases; the third is to strengthen seedbed management and adjust temperature and humidity to create an environment suitable for the growth of stevia but not conducive to the development of diseases. For infectious diseases, carbendazim, methyl thiophanate and chlorothalonil can be prevented from spraying at the initial stage of the disease, and attention should be paid to ventilation and dampness reduction after medication.

The above is the introduction of the causes and control methods of the dead seedlings of stevia. I hope it can help you. If you want to know more about it, please follow us.