How to prevent and treat Sclerotinia sclerotinia sclerotinia with American ginseng? Ginseng scleroti

Sclerotinia sclerotinia mainly infects ginseng roots for more than three years, and seedlings are rarely damaged.

1) Disease: Sclerotinia sclerotinia infects only underground roots and rhizomes. The roots are infected with soft rot, and there is a small amount of white hyphae on the surface at first, and then irregular black mouse fecal granular sclerotia are formed. In the end, the corruption of the internal organization disappeared, and only the outer skin remained.

The disease develops rapidly, it is difficult to identify early, and the early stage is almost a healthy plant, and when it is found to be wilted, the ginseng root has festered. Once the disease occurs, it spreads very quickly (Figure 36). (2) The cause of the disease is that the sclerotinia overwinters on the diseased residue and in the soil, and begins to be infected at the ground temperature in early spring and late autumn, and the disease is easy to occur in early spring and late autumn when the soil is low and wet, and generally occurs before the emergence of seedlings after the soil thaws in April and June, and basically stops spreading after June.

When the soil temperature is above 2, the disease will begin to be infected, the disease will be severe when the soil temperature is 6 8, and the disease will be mild or stop spreading when the soil temperature is more than 15. When the soil temperature is above 20 and the humidity is too high, the roots of the diseased ginseng will rot quickly. The disease is at its peak from soil thawing to emergence.

Soil moisture, low ground temperature, poor drainage, poor air permeability or too much nitrogen fertilizer are all prone to this disease, excessive precipitation before soil freezing, and then cooling and freezing, bed soil moisture is also susceptible to disease. (3) Prevention and control methods Strengthen field management, dig drainage ditches, prevent excessive water from flowing into the ginseng bed after the ice and snow melt in early spring, and avoid over-wetting and compaction of the soil. When transplanting, pay attention to protect the ginseng seedlings, prevent the seedlings from frost damage, reduce disease resistance, and remove the cold-proof materials appropriately and early when passing through the wet area.

Loosen the soil frequently, increase soil permeability, and increase soil temperature.

In spring and autumn, pay attention to prevent slow sun freezing. If diseased plants are found in the field, they should be uprooted immediately and the surrounding soil should be disinfected to control the spread of the disease. Pharmaceutical prevention and control:

After the cold-proof soil is placed, disinfect the bed surface, bed groove, walkway and the surrounding area of the ground with 1% copper sulfate solution. One week before transplanting American ginseng, 20 grams of 50% carbendazim wettable powder were evenly mixed into each square meter of ginseng field, which had a good effect on the prevention and control of Sclerotinia sclerotinia sclerotinia of American ginseng.

Fig.36 Symptoms of sclerotinia sclerotiorum.

Implement crop rotation to avoid heavy cropping. At the beginning of winter, the soil is deeply cultivated (about 50 cm) and the sclerotia are buried deep to lose their vitality. The planting should not be too dense to facilitate ventilation and light transmission and reduce humidity. 1 200 chloronitrobenzene poisoned soil can also be sprinkled around the rhizosphere for soil disinfection.

At the beginning of the disease, 50% Tobuzin 500 800 times liquid spray, or 50% Dacrin wettable powder 1000 times liquid spray, spray once every 10 15 days, spray 2 3 times continuously, can control the spread of the disease. The focus of the spray is on the middle and lower parts of the plant and the ground.

Ginseng sclerotinia occurs frequently, how to prevent and treat it? Ginseng sclerotinia is one of the more common soil-borne root diseases that occur during ginseng planting, which mainly harms the root and stem base of ginseng for more than three years, and will lead to root rot and pruning death. At present, chemical agents are mainly used for prevention and control in production, but it is necessary to pay attention to the selection of high-efficiency, low-toxicity and low-residue agents, so as not to cause excessive residues and affect the effect of ginseng medicine.

The main prevention and control measures are as follows: 1. Strengthen cultivation management. Choose well-drained, high-lying land for planting, pay attention to drainage in the rainy season to prevent excessive soil moisture; Reasonable crop rotation, reasonable fertilization, weeding, keeping the ginseng land clean, etc., rainy season; If a diseased plant is found, it should be pulled out immediately, taken out of the ginseng site for destruction, and the disease hole should be disinfected with quicklime.

2. Biological control. At present, the commonly used biological agents mainly include Bacillus subtilis, Bacillus cereus and Trichoderma. 3. Prevention and control of chemical agents.

Chemical agents can be treated with sclerotinia sclerotiorum, propiconazole, tebuconazole and other agents.

Of course, biological agents and chemical agents can be reasonably mixed, such as using Bacillus cereus and sclerotia in a ratio of 3:1 or 2:3, which has obvious synergies and is conducive to reducing chemical pesticide residues in ginseng.

Sclerotinia sclerotinia is the most common disease of ginseng, disease prevention starts from the selection of land, we must choose a plot with slope, drainage and waterlogging, ground disinfection should be carried out when preparing the land, the most effective and no residue method is to use quicklime, the whole plot is covered with a thin layer, before the ginseng is unearthed, it is necessary to do a good job of loosening the bed before the ginseng is unearthed, increase the evaporation of water and improve the ground temperature, and then disinfect the ground again, to use a special fungicide without residue, after the emergence of seedlings, after the foliar aging is carried out once a week after spray sterilization and disinfection, Sclerotinia sclerotinia can only be prevented, not cured, and there is no specific drug for this aspect so far, so if you find that the ginseng should be pulled out in time, and then disinfected with quicklime to prevent the infection of nearby ginseng. The above is mine, I hope it helps you.

When planting, you should choose some soil with good drainage, and in the rainy season, you should also pay attention to drainage, remove the surrounding weeds, and choose to spray some pesticides.

Pesticides. Because pesticides can be a good way to prevent and prevent sclerotinia disease, pesticides should be used to prevent and control it.

When planting, some pesticides should be sprayed, and more bactericidal drugs should be used, so that they can play a good role and can also be well prevented.

The occurrence of ginseng sclerotinia is not common, and it mostly occurs in low-lying land, shady slopes and downhill plots of mountains, causing harm to ginseng.

1) Pathology. The disease mainly occurs on ginseng roots that are more than four years old, and seedlings are rarely damaged. It mainly harms spores, roots and rhizomes. A small amount of white velvety mycelium was born in the root of the infested ginseng, and then the interior quickly disappeared, leaving only the outer epidermis, and irregular black mouse fecal-like sclerotia were formed on the diseased body.

The disease spreads so rapidly that it is difficult to identify early, and the aboveground parts are almost the same as those of healthy plants in the early stage, and by the time the plants show wilting symptoms, the underground roots have already festered (Figure 17).

2) The cause of the disease.

Sclerotinia sclerotinia is a fungus of the genus Sclerotinia sclerotiorum. The hyphae are white, the sclerotia are black, and they vary in shape and size. Ascomycetes are formed on the sclerotia and are funnel-shaped, pale brown at the beginning, and shallow disc-shaped, brown when mature.

Ascospores are monospores, colorless, and oval. The development temperature of pathogenic bacteria is 4 30, and the optimal temperature is 15. The disease generally occurs at its peak from soil thawing to emergence, and basically stops after June.

Low temperature and humidity, low-lying terrain, poor drainage, and excessive nitrogen fertilizer are all susceptible to this disease. Before emergence, if the soil temperature is low and the humidity is high, it often causes an epidemic of sclerotinia sclerotinia disease. The sclerotia overwinters in the diseased roots or soil, and in the spring of the second year, the soil is low and humid, and begins to produce hyphae to infect the ginseng roots, causing harm.

3) Prevention and control methods.

Choose a plot with good drainage and high and dry terrain to plant ginseng, dig a good drainage ditch to prevent water accumulation in the ginseng bed, put cold protection materials in a timely manner, loosen the soil in advance to increase the ground temperature and reduce soil moisture.

Before emergence, the bed surface should be disinfected with 1% copper sulfate solution or 1 1 100 Bordeaux solution, and 50% carbendazim wettable powder should be used for soil disinfection during transplanting or loosening, and 10 15 grams per square meter can prevent ginseng sclerotinia sclerotinia disease.

Diseased plants are immediately excavated, and disease-free soil is replaced in the disease area or the diseased holes are disinfected. It can also be smoked, and the sclerotia will all die under 60 conditions and will no longer be infected.

Fig.17 Ginseng sclerotinia sclerotinia disease.

1.Root of the disease 2Pathogenic bacteria.

Implement crop rotation to avoid heavy cropping. At the beginning of winter, the soil is deeply cultivated (about 50 cm) and the lead macro sclerotia is buried deep to lose its vitality. The planting should not be too dense to facilitate ventilation and light transmission and reduce humidity.

1 200 quintozene-poisoned soil can also be sprinkled around the rhizosphere for soil disinfection.

At the beginning of the disease, the disease can be controlled by spraying 50% Tobuzin 500 800 times liquid spray with 50% Dacrin wettable powder, spraying once every 10 15 days, and spraying 2 3 times continuously. The focus of the spray is on the middle and lower parts of the plant and the ground.