Control techniques of Diseases and insect pests of Panax Notoginseng

Disease prevention and cure

(1) Panax notoginseng root rot

Symptoms: there are often two kinds of symptoms of the disease in the field: (1) abnormal leaf color at the initial stage of aboveground, leaf wilting, leaf yellowing and shedding, and underground rot; (2) local root damage of underground root, leaf drooping to one side, wilting, pulling out in time, it can also be processed and used, otherwise the whole root rot. Disease regularity: seedling, diseased root residue and soil infection can occur all year round, and the two peak periods are from March to April and from August to October. Because the disease is a soil-borne disease and its pathogenic factors are complex, four kinds of pathogens have been identified, including bacteria and fungi. Among the four pathogens, the pathogenicity of bacteria was the strongest, which could be infected from seedling unearthed in early spring to wilt.

Poor soil preparation, heavy soil viscosity, poor drainage and seedling damage, and a history of disease may lead to the occurrence of root rot.

The occurrence and development of root rot of Panax notoginseng depends to a large extent on environmental conditions. When the temperature is 15Mu20 ℃ and the relative humidity is more than 95%, it will cause the occurrence or epidemic of root rot, the light transmittance of shade shed is too large, and the disease is serious. The disease of continuous cropping was more serious than that of rotation and new cropping, and the longer the continuous cropping was, the more serious the disease was. Fertilizer types, fertilization methods and field management measures directly affect the occurrence and spread of diseases, so a single chemical control measure is often difficult to be effective in production. At present, the most ideal way is to take comprehensive control measures with the combination of agricultural control and chemical control.

Prevention and control measures:

The main results are as follows: 1. The most suitable soil for planting Panax notoginseng in suitable land is sandy loam, and the PH value is 6Mel 7 (moderately slightly acidic soil). Plots should have a certain slope to facilitate drainage in the rainy season; do not choose plots that have been planted with Panax notoginseng in 5 years.

2. Choosing healthy seedlings to carry bacteria or storing for too long after digging is one of the major causes of root rot. therefore, it is very important to choose healthy seedlings and transplant them in time. For the selection of healthy seedlings, it is also necessary to check whether there are rotten diseased plants in the seedlings and whether there are diseased plant residues in the seedling field. If so, they should be cleared in time, and the seedlings should be treated with 1 ∶ of Manganese Zinc Manganese Methyl or carbendazim for 30 minutes and then transplant with drugs.

3. The application of mature fertilizer and timely watering of undermature farm manure is one of the reasons for rotten roots and buds. Therefore, if you use farm manure such as pig manure and oil, you must pile it up for more than 3 months to make it fully mature and apply less nitrogen fertilizer.

4. To strengthen the management in winter, the disease remains should be removed and disinfected in time, which can be treated with 1 ∶ of carbendazim and Manganese-Zinc solution.

5. Chemical control is an auxiliary measure to control root rot of Panax notoginseng, which can be used with bactericidal agents Ye Ku Jing, Ye Kun Ning, fungicides Dexong, carbendazim and so on. According to the experiment, 10% Ye Ku Jing (Ye Ku Ning) + 70% Dixong 1 kg of medicinal soil per mu was applied, and the control effect was more than 70%.

(2) Black spot of Panax notoginseng

Symptoms: the injured part showed an oval light brown spot at the beginning, followed by a dark brown spot, which expanded up and down, sunken, and produced black mildew, and finally twisted and died.

Disease regularity: carrying bacteria in diseased seeds and seedlings is the main way of transmission of black spot. The plants can germinate and infect when the temperature is 18 ℃ and the relative humidity is 80%. The incidence of high temperature and humidity is serious, continuous rainfall or typhoon rainstorm will aggravate the epidemic of the disease. Light transmittance in shade shed, fertilization and other cultivation measures directly affect the occurrence and decline of the disease.

Prevention and control measures:

The main results are as follows: 1. When selecting and collecting disease-free seeds, choose the seeds of disease-free fruit to eliminate diseased fruit and fruit seeds.

2. Seed seedling treatment seed seedling is the source of pathogen, so seed disinfection must be carried out when sowing. The seeds can be soaked in 58% Ruidu mold manganese zinc or 64% alum 1 ∶ for 30 minutes.

3. Eliminate and block the disease center to check frequently, find the center disease plant, remove the center disease plant immediately, and carry out chemical protection around it, in order to effectively control the development of the disease.

4. Strengthen cultivation management and reasonable close planting, and ensure uniform light transmission in the seven gardens. Excessive light transmission is easy to induce diseases, so it is best to choose sunshade net cultivation.

5. clean up the withered branches and leaves and mulch in the seven orchards in time after doing a good job of planting in the field, and spray to prevent.

6. during the leaf development stage of Panax notoginseng seedlings, it was found that the diseased plant of black spot was the disease center. The diseased plant in the disease center is the best time to start spraying, and the frequency and interval of medication should be determined according to prediction and climatic conditions. The spray is usually sprayed every 10 days. There are many pesticides used for the control of black spot. At the initial stage of the disease, the following pesticides are used alternately or mixed with two of them (except polyantimycin): 64% disinfectant alum wettable powder 1 ∶ 300 ∶ 500x solution, 64% Ruidu manganese zinc wettable powder 1 ∶ 300m 500x solution, 40% sclerotia net wettable powder 1 ∶ 400x solution, 1.5% multi-antimycin wettable powder 1 ∶ 500x solution 40% Dasheng wettable powder 1 ∶ 500x liquid.

Routine examination method of black spot disease of Panax notoginseng

1. Inspection instrument microscope

2. Testing agents 95% alcohol, glacial acetic acid, saturated chloral hydrate

3. The test method: randomly cut 5 pieces of Panax notoginseng leaves in the field, put them in the same amount of 95% alcohol and glacial acetic acid mixture, fixed for 24 hours, and then immersed in saturated chloral hydrate solution. After the tissue is transparent, the conidia of black spot disease can be observed, so as to predict the occurrence dynamics of black spot disease and guide the use of drugs in the field.

(3) Panax notoginseng blight and quenching disease

Both of them are the main diseases in the seedling stage of Panax notoginseng, and their symptoms are similar, so it is difficult to distinguish them.

The disease usually occurred at the base of the stem of the seedling, that is, at the junction of dry and wet soil away from the topsoil layer 3-5cm. After the invasion of the pathogen, the tissue of the susceptible part softened, and the base of the stem showed a yellow-brown sunken spot at the beginning, which gradually went deep into the stem and rotted, resulting in the lodging and death of the seedlings.

At the initial stage of the disease, the affected part showed a water-immersed dark spot, and the stem shrank and softened and died; when the humidity was high, a layer of gray-white mildew often appeared on the surface of the injured part. Both blight and quenching occur in the stem of Panax notoginseng at seedling stage, but the disease occurs at the junction of dry and wet soil 3-5cm from the topsoil, while quenching occurs near the ground of the aboveground stem, which is one of the main characteristics of the two different diseases.