Prevention and Control of Diseases and insect pests of Chinese Medicinal Materials

diseases

Leaf-rot: This disease is easy to occur in seedling stage, but rarely occurs in mature plants. The main cause of the disease is soil moisture or continuous rain caused. The disease spreads rapidly in a humid climate. The disease site is mainly in tender leaves, the disease spot is light green, scalded, and later turns brown and withered.

Control methods: (1) early disease timely cut off the diseased leaves, serious when pulling out plants. (2) Chemical control, 1∶1∶100 Bordeaux mixture or 0.2~0.5 Bordeaux sulfur mixture can control the disease development. Once every 7 to 10 days, 2 to 3 times continuously. (3) Remove sundries in the ditch, dredge and remove accumulated water in time; uncover the shade in the morning and evening on cloudy and sunny days, increase ventilation and illumination, accelerate water evaporation and improve disease resistance. (4) The seedlings cannot be planted too densely.

Root rot: This disease mainly affects seedlings, and mature plants rarely suffer from disease. The cause of disease is similar to leaf rot. High temperature and humidity, harm is very strong, seedlings die in pieces. The diseased part is at the base of rhizome, and the base of rhizome is rotten.

Control methods: (1) Improve ventilation and light transmission conditions, ditch drainage in time, increase light appropriately, improve plant disease resistance and reduce diseases. (2) In the early stage of the disease, remove the diseased plants, sprinkle lime for disinfection and sterilization, and control the spread of germs. (3) Chemical control: soil disinfection with 1% copper sulfate solution, spraying 1∶1 ∶120 Bordeaux mixture on leaves, alternately spraying 500 times metalaxyl and 500 times 25% carbendazim WP, once every 7~10 days, 2~3 times continuously.

Sunburn disease: the leaves of alpinia oxyphylla are tender on the surface. If the shade degree is poor or the plant is over-applied with nitrogen fertilizer, it will cause sunburn disease once it is exposed to strong light. Symptoms: leaves desiccate and wither, tender heart buds wither and scorch until the plant dies. According to the investigation of wild intelligence in the nearby mountain areas in Xinglong Overseas Chinese Farm, the incidence of wild intelligence sunburn was 0.5%~1% in the places where the shade degree was less than 80% during the natural regeneration of tall trees. According to the investigation in Wanning and Lingshui counties, artificial cultivation of A. oxyphylla has poor shade, and sunburn is extremely common, with an incidence of 20%~30%, and serious cases up to 70%~90%. The causes of sunburn disease are as follows: one is poor shade, and there is no good shade tree planted before planting in plain areas; Second, planting intelligence on hillside, afraid of insufficient sunshine, cutting down too much or all the original trees; Third, choose rainy days for planting, or drought without enough root water, or simply no watering, less rainfall after planting, exposure to hot sun, and not timely watering, sunburn disease will seriously occur.

Control method: (1) plant fast-growing plant all round, if cajan bean (hainan calls willow bean), mountain edamame, roselle, wild edamame, cassava, wait, serve as short-term shade. The concrete method is: planting 1 - 2 cajanus cajan and the like at 30 cm of the east and west sides of the intelligence plant. (2) Replanting fast-growing trees as shade trees, such as neem. (3) Eupatorium odoratum can be planted around the plant to shield the strong sunlight in the east and west direction. At the same time, Eupatorium odoratum can be buried as green manure to increase organic matter, improve soil texture, improve water storage capacity, promote the growth of intelligence, and enhance resistance to diseases. (4) Do a good job of irrigation and drainage facilities, divert water or pump water during dry seasons to keep the soil moist and reduce disease.

Rhizoctonia solani: Disease caused by a fungus, mainly affecting leaves, with an incidence of 90% and a mortality rate of more than 35% in seriously ill areas. Pathogens spread through rain, running water, farm implements transfer and the use of contaminated fertilizers. Sowing too dense, poor light and ventilation, too wet seedbed soil is conducive to disease occurrence; higher temperature (above 28℃), excessive rainfall climatic conditions are easy to cause disease epidemic.

Control methods: The seedbed should be selected from a place with high terrain and good drainage; if the old seedbed is used, 15-20 days before sowing, it is necessary to loosen the bed soil and pour 100 times of formalin solution, pour 5 kg per square meter, then cover the plastic film for 4-5 days and remove it, and sow after about 10 - 15 days; the fertilizer used should be decomposed, and the sowing should be uniform and not too dense; the seedbed should not be watered too much to avoid excessive wetting of the bed soil; heat preservation should be done well in winter to prevent the seedlings from freezing; At the early stage of disease, 5% lime water or 1∶50 phenanthroquinone fine soil was sprayed on the soil around the diseased plants or 50% carbendazim wettable powder 1000 times solution or 1∶1∶100 Bordeaux solution was sprayed on the diseased plants; after the severely diseased plants were pulled out, lime powder or 50% thiophane 1000 times solution was sprayed on the soil around them.

Ring blight: caused by a fungus. From seedling to fruiting, it is susceptible to infection, and the old leaves are infected first. The pathogen overwinters on the diseased plant and its residual tissue by mycelium or conidia disk. When the environmental conditions are suitable in the following spring, the pathogen produces conidia and spreads by wind and rain, mainly invading from wounds to cause disease. High temperature and rainy season is conducive to the spread of diseases, especially the incidence of perennial shade and humidity or poor drainage; extensive management, serious sun exposure, poor growth potential of plants easy to disease.

Control methods: strengthen management, apply fertilizer, remove accumulated water, remove fallen leaves, and properly shade; spray 50% Diammonium WP 800 times or Bordeaux mixture 1∶1∶100 or 75% Junqing 1000 times or 50% Thiophanate WP 800 times at the initial stage of disease.

Root-knot nematode: caused by a root-knot nematode. It mainly damages the roots of seedlings.

Control method: select disease-free seedlings; implement rotation; deeply turn the seedling field before sowing, remove weeds inside and outside the nursery, apply decomposed fertilizer to reduce infection sources; 10 days before sowing, use 80% dichlorobromopropane emulsion 3kg mixed with water 100kg per mu, open the ditch and apply it, and cover the soil after application.

pest

Puzzle butterfly (also known as "bract worm"): to damage the leaves with larvae, first leaves into a roll-shaped bract, after feeding in the bract, so that the leaves were notched or hole-shaped.

Control methods: manually remove the worm roll leaves or kill larvae with hand pinch; larva stage, can try 90% trichlorfon 800-1000 times solution or 80% dichlorvos 1500-2000 times solution spray, every 5-7 days once, continuous 2-3 days.