First, the symptoms of disease

1. Blight. Freshly emerged seedlings and large seedlings can be victimized, especially in the middle and late period, the base of the diseased seedlings becomes brown, the posterior disease department shrinks finely, and the stems and leaves wilted and die. Slightly severe diseased plants or 5–10 days after planting, the base of the diseased plant produces dark brown oval lesions at the base of the diseased plant. The diseased plants are wilted during the day and recover at night. The lesions gradually sink and continue to expand, and the base of the stems shrinks around the stem 1 week later. Fine, the stems and leaves of the aboveground plants are wilted and dry, and they are not fallen down. After the onset of colonization, the tissue rotted when the humidity was high, the diseased part had a light brown spider silky mildew layer, and later formed sclerotia.

2. Stem rot. Mainly injurious to large seedlings or tomato stem base or underground main lateral roots after planting. The diseased part is dark brown at first, then spreads around stems or rhizomes, rots to the cortex, yellows on the ground, and the nutrient supply is insufficient after fruit enlargement, gradually from the top of the plant. Weakness, especially at noon, manifested clearly and died after 1 week. The surface of the diseased part often forms brown sclerotia.

Second, the pathogen

The pathogen of the two diseases is Rhizoctonia solani, a fungus that is a semi-known fungus, and it does not produce spores. It mainly spreads and reproduces with mycelia and sclerotia; the sexual state is melon, and it belongs to basidiomycetes. Asian fungus.

Third, the law of occurrence

The pathogenic bacteria mainly overwinter in mycelium or sclerotia with mycelia or sclerotia. Germs are more prototypical in the soil and can survive for 2 to 3 years. When the conditions are appropriate, sclerotia germinates and hyphae infest the seedlings. The bacteria spread in the field by rainwater, irrigation water, agricultural equipment, and compost, forming repeated infections. The suitable growth temperature of the diseased seedlings was 24°C. When the temperature was below 12°C or higher than 30°C, the growth was inhibited. The spring and autumn nursery period seedbed bed or planting room environment and disease are closely related, seedlings or greenhouses, high temperature, soil moisture, the application of unripe fertilizer, and poor ventilation, light, the disease most likely to occur, and cause the epidemic. In this county, the onset of tomato blight was earlier and the incidence of tomato stem rot was slightly later. The two diseases began to occur in early fall in the fall shed, and peaked in late October and early November. In the middle and late November, stem-based rot was the main disease, and the development of disease was slow.

Fourth, comprehensive prevention

Greenhouse tomato production is a systematic and comprehensive technology with high technological content. Therefore, prevention and control can not rely solely on pharmaceuticals, must carry out agricultural, ecological, pharmaceutical and other comprehensive supporting technology for full control, can play a better control effect.

1. Agricultural control

(1) Cultivate disease-free strong seedlings. The field soil outside the shed was used to prepare nutritious soil for seedling cultivation, combined with planting time, suitable for nursery, and strengthened seedbed management. Bed temperature should be controlled within 30 °C, timely ventilation and humidity, pay attention to seedling disease prevention and hardening seedlings, to avoid weak seedlings, seedlings or seedlings are too long.

(2) Greenhouse soil disinfection. Before the preparation of the site, we remove the sick and weeds in the shed. Deeply turn the soil (especially when it is used as a heavy land) and do a good job of soil disinfection. Apply 20% carbendazim 3kg, 50% dexamethasone 1kg, or 40% quinolinic nitrobenzene per 667 square meters, and Fumei Double 1:1 mixed fine soil 12.5kg to make up the medicinal soil. Before sowing, spread 1/3 of the medicinal soil into the sorghum surface and sow the remaining medicinal soil onto the seeds after sowing so as to prevent soil from contaminating the soil.

(3) Shed room high temperature treatment. 15 - 20 days before planting, buckle up the shed, close the tuyere, close the greenhouse for 15 - 20 days, and conduct disinfection of the greenhouse so that the temperature in the shed can reach 60°C or higher for 5 - 7 days (usually referred to as "baking shed"). ) To form a long-time high-temperature environment in the shed to completely kill the remaining pathogens and reduce the occurrence of diseases.

(4) Strengthen cultivation management

1 Increase organic fertilizer and improve soil structure. Tomatoes grow fertile, loose, and absorb more nitrogen, phosphorus, and potassium. Therefore, decomposed organic fertilizer should be applied as base fertilizer and phosphorus and potassium fertilizer should be added. Improve the soil, increase soil water retention, drainage and permeability, avoid applying fertilizer, cause soil compaction and reduce nutrients. Planting is not too dense. Infinity-growing varieties are planted at around 4,000 plants per 667 square meters. Before the tomato blossoms, evenly spread a layer of grass ash to the shed to reduce the humidity and raise the soil temperature. Potash supplements enhance plant resistance to disease.

2 Scientific watering. Watering once should not be excessive, keeping the soil moisture appropriate. Advocate small water pouring, avoid flood irrigation, drip irrigation or plastic film can be used to cover the dark water technology, reduce the humidity within the greenhouse. Diligent cultivator to improve soil permeability. It is necessary to pay attention to insulation and cold, but also pay attention to ventilation and cooling to reduce the incidence of disease.

2. Ecological control. Strengthen ventilation management. The temperature of the greenhouse is maintained at 20-25°C during the day and the temperature drops to 15--17°C after closing the greenhouse at night. On cloudy days, the temperature should be ventilated and ventilated.

3. Chemical control. At the beginning of the disease, timely medication control, use 20% of the tolaponin 1200 times or 5% Jinggangmycin agent 1500 times or green Hunter hymexin or 50% acetaminophen WP 1000--1500 Doubly liquid, alternately used, irrigated once every 7 days, even irrigation 3 - 4 times. After the onset of tomato stalk rot and blight, it is also possible to apply a seed dressing double or green chlorthiazolone herbicide soil at the base of the stem. Medicinal soil formula: Apply 40% of the surface soil per square meter, apply 9g of double wettable powder 9g, mix thoroughly, cover the heap at the base of the diseased plant, bury the diseased part, promote the growth of adventitious roots above the lesion, and delay. Life, reduce losses.

Electrochemical Meter

Electrochemistry meters measure the pH, oxygen, temperature, conductivity, and more. These equipment classifeid to benchtop and portable handheld metersfor various needed. Allow the user to test the water quality with simple step-by-step technology.

Electrochemical Meter,Ph Meter Odm,Portable Meter,Redox Meter, Conductivity Meter odm

INESA Scientific Instrument Co., Ltd , https://www.inesarex.com