What Are the Medical Uses of Asparagus Racemosus?
Asparagus stem blight is a devastating disease that occurs in almost all asparagus producing areas in China. Asparagus stem blight is a cancer called asparagus. When it is light, the plant dies sporadically and its yield is reduced. When it is heavy, the whole field is destroyed and the yield is lost, which causes huge losses to the majority of shoot farmers.
Asparagus stem blight
- Chinese name
- Asparagus stem blight
- Alias
- Asparagus stem rot
- Symptom
- Stems and leaves dry, severely massed, like a fire
- Pathogenic bacteria
- Aspergillus asparagus
- Asparagus stem blight is a devastating disease that occurs in almost all asparagus producing areas in China. Asparagus stem blight is a cancer called asparagus. When it is light, the plant dies sporadically and its yield is reduced. When it is heavy, the whole field is destroyed and the yield is lost, which causes huge losses to the majority of shoot farmers.
- Asparagus stem blight is also called asparagus stem rot.
- The causative pathogen of Asparagus stalk blight is Asparagus spp., Which widely exists in nature, and will be widely transmitted under suitable conditions. A large number of stem blights must coincide with each other. A large number of pathogenic bacteria are the primary conditions for the disease. The infection and spread of pathogenic bacteria require humidity, including rainfall and watering. In addition, the air circulation and the temperature of the pathogens infect the pathogenic bacteria. The influence of pathogens and transmission is very large; the initial vector of pathogen infection is a large number of young asparagus stems and seedlings. When these several factors are matched, stem blight will occur in large numbers [1]
- 1. The area of poor resistance is large: the main varieties of asparagus cultivation are not first-generation varieties, accounting for 80% of the total area, and the disease resistance decreases year by year. Once the environment is suitable, it will cause a large area of disease.
- 2. Conditions are good for the onset of disease: the temperature range for bacterial growth is 16-35 , and the appropriate temperature is 23-26 . Above 35 ° C or below 10 ° C, conidia do not germinate. Spring temperature is closely related to the onset of the disease sooner or later. Especially the high temperature and high humidity in July, August, and September is the vegetative growth stage of asparagus, and it is also the peak period of germ infection. The diseased plant rate basically increased with the increase of the number of rains. The peak of the disease occurred once every 10 days after the rain.
- 3 Heavy N fertilizer, light phosphorus and potassium: Too much nitrogen fertilizer and over-growth in nutrition. Most of the bamboo shoot farmers, in pursuit of immediate benefits, re-apply N fertilizer or only N fertilizer to make the bamboo shoots grow densely, and the stem cell walls are tender and thin. It is very easy to infiltrate. According to the investigation, the application rate of N, P and K three-element compound fertilizer was only 10%, and only urea was used, and the incidence rate was 58%.
- 4 Cleanliness is serious: Most farmers have cleared the garden in time, but there are still some farmers who do not clear the garden or the garden is not completely and timely. According to investigations, the dead branches of asparagus were eradicated and burned out of the ground, and the garden was completely cleared. The incidence was only 5% in the second year. In spring, the garden was cleared before closing in March, and the diseased plant rate was 58%.
- The pathogenic pathogen of Asparagus stem blight was Asparagus spp. The bacteria overwinter with conidia or hypha on diseased plants or in soil. In the coming year, the conidia will fly out of the sporule and pass through various transmission channels such as rain and farming tools. After the first damage to the tender stem, the spores released from the mature conidia will be washed out by the rain, and the airflow and rain will splash back. It causes secondary infection to the base of asparagus stems. Pathogens are most likely to invade when the stems are young, and the infection rate is usually highest when the young stems grow for 10 days. During the entire growing season of asparagus, the average period of infestation is 10-12 days, and the germs can be repeatedly infected more than 10 times. The growth and decline of the disease can be divided into two stages in one year. The disease rate is still low at this stage, and the disease development is slow; the second is the severe disease period, that is, 40 days after the onset of disease. The diseased plant rate in the field reaches more than 40%. This period starts from late July or August. At the same time, the bamboo shoots gradually become denser. The rainy season is approaching, which creates very favorable conditions for disease occurrence. Late onset has a great effect.
- Control of asparagus stem blight,
- Asparagus stem blight
- 1. Reducing pathogenic bacteria is the most important factor in preventing and controlling asparagus stalk blight. Generally speaking, the incidence of new shoots is relatively light, the source of old shoots is large, and the incidence is early and severe. There are two main sources of germs in the new bamboo shoot field. One is the seed-borne bacteria. The other is that the germs in the old bamboo shoot area are transmitted by wind or rain. Therefore, keeping the asparagus field clean and hygienic, removing old stalks and diseased plants from the field, and quickly drying and burning the diseased plants are very important for reducing pathogens and are the most important disease control measures. For plots that have been infected with stem blight, special attention should be paid to clearing the garden in winter and sterilizing the stubble. Because the stem blight pathogen can overwinter on the diseased plant and become the source of the initial infection in the following year, in order to reduce the source of disease, when the garden is cleared in winter, it must be thoroughly and cleanly. And focus on burning. It is best to clear the garden in advance to the end of November, and after the end, use 500 times 45% carbendazim solution, 0.4% Bordeaux solution (0.2 kg copper sulfate + 0.2 kg quick lime + 50 kg water) to disinfect the soil.
- 2. We must do a good job in the management of the bamboo shoots in summer to reduce the incidence factors. In the rainy season, we must pay attention to drainage and prevent water accumulation in the fields. Weeding and weeding should be timely removed and diseased stems removed in time to control the amount of female stems left in the bamboo shoots. Generally, the female stems with a thickness of 1.2 stems should not exceed 120 per 15 square meters. The second year after planting should not be interplanted with other crops to prevent the field from being blocked, ventilated, and poorly lit. Reasonably adjust the harvesting period so that a large number of unearthed young stems are staggered from the Meiyu period, and excess or diseased young stems should be removed in time to reduce bacterial infection and delay the onset of disease.
- 3 To rationally fertilize, we must pay attention to the application of organic fertilizers and appropriate amounts of potassium and phosphate fertilizers, control the application of nitrogen fertilizers, promote the robust growth of plants, and improve disease resistance. According to our many years of experiments, adding potassium and molybdenum fertilizers has a significant effect on enhancing host disease resistance and increasing yield.
- 4 The principle of "prevention is more important than treatment" should be implemented in the prevention and control of pharmaceuticals. After the tender stems are drawn out, they should be sprayed in time to obtain good results. The spray must be uniform, mainly spraying the tender stems, stems and branches, and never spraying branches and leaves. Spray once every 5-7 days at the beginning of the disease, and spray once every 1-3 days at the peak of the disease. In case of rain within 4 hours after spraying, spray again. In order to avoid resistance, 2-3 kinds of medicines can be used in rotation.
- The pesticides used in the production to prevent stem blight are: 50% carbendazim 500-600 times solution for spraying during soil disinfection and disease; 70% mancozeb zinc wettable powder 175-250 g per mu Spray control; 1000 times liquid + 75% chlorothalonil 600 times liquid spray; 50% bentelite EC, 800-1000 times liquid; spray control; Ditolatan wettable powder Double dilution solution spraying; 0.4% Bordeaux solution (that is, 0.2 kg copper sulfate + 0.2 kg quicklime + 50 kg water) spraying; copper hydroxide: 1.0-1.4 kg / ha application ratio add enough water to completely cover the asparagus plant clusters. It should be applied under high humidity with free moisture in the asparagus plant clusters, and the application interval should be 7-14 days. Can be staggered with mancozeb, staggered in time.
- By studying the symptoms and biological characteristics of asparagus stem blight in Chongming Island, the pathogen was identified as (PhomopsisasparagiSacc.). Studies on biological characteristics show that the suitable temperature range for the growth of the pathogenic mycelia is 15-30 ° C, the optimal temperature is 20-25 ° C, and the optimal pH value is 6. Conidia did not germinate in water droplets, and the lethal temperature was 49 for 10min. The 12h light-dark alternation is beneficial to the growth of hyphae and the production of conidia. The plate method and paper stack method were used to determine the bacteriostatic effect of 10 kinds of fungicides. The results showed that 75% Daconin 700 times solution had the best inhibitory effect, followed by 65% Haoxin 500 times solution, and 12.5% Lectrabacterium 3000 The double liquid effect is the worst. [2]