Symptom manifestation and comprehensive control of Botrytis cinerea in flowers, fertilization techniques and methods of edible fungi

Botrytis cinerea is one of the most common diseases in flower production. It often occurs during the growing season of flowers, especially in winter and spring. Pathogens can infect any part of the plant. If the cultivation management is relaxed, it is more conducive to the occurrence and popularity of the disease. In serious cases, it can cause a large number of flowers and leaves, affect the flowering of plants, reduce the ornamental value, cause great damage to the character and yield of flowers, and seriously restrict the economic benefits of flower production.

1. Damaged flower varieties

Gray mold damage a variety of herbs, herbaceous flowers, such as Rieger begonia, New Guinea balsamina, cyclamen, melon, Phalaenopsis, poinsettia, primrose, aster, begonia, dahlia, fuchsia, purple-flowered flowers, dahlia, geranium, gladiolus, Stagelina and other 50 kinds of flowers.

II. Symptoms of Damage

The disease damages leaves, flowers, pedicels, petioles, and tender stems. It also damages fruit. Make leaf, flower erosion, tender stem break, drop or lose the commodity value of flowers. Gray mold damage leaves, often in the leaf edge or leaf tip appear dark green water-like spots (such as boiling water burns), and continue to expand into the leaves, humidity caused brown erosion, covered with gray mold. When the humidity becomes small, the affected parts become brown, light brown, dry yellow and other dry shapes (depending on the flower variety), brown, light brown, white and other water-stained patches appear on the petals (depending on the flower variety), and then erosion. Brown patches appear on tender stems or stems with high water content. If the temperature and humidity are suitable, the disease spots will spread quickly, causing brown erosion at the diseased part, breaking or lodging of branches and stems, wilting and death of parts above the diseased part, and death of the whole plant when the disease is serious. No matter what part of the flower disease, in high humidity conditions, the disease grows gray mold is their common feature, but also an important symptom of the disease.

III. Pathogenic bacteria and pathogenesis

The pathogen is Botrytis cinerea, and the gray powder emerging from the diseased part is the conidia and conidia of the pathogen. conidium slender, erect, branched, 1. 3 mm, terminal cells dilated as globose, pedunculate, conidia bearing, conidia aggregated into grape spikes, conidia ovoid or ellipsoid, rarely globose, colorless to pale. The fungus overwinters in the form of mycelium or conidia and sclerotia attached to the diseased body or left in the soil. The optimum temperature for the growth of this bacterium is 10-32℃, the minimum temperature is 4℃, and the relative humidity should be maintained at 90%.

A large number of conidia produced by the diseased part in wet condition were the main pathogens of reinfection. Warm and wet conditions are the main conditions for the epidemic of gray mold. The pathogen overwinters on the diseased bodies in the soil. The mature conidia are transmitted by air flow, rain, irrigation water, shed dripping and agricultural practices. The pathogen has strong pathogenicity to flower organs and leaves, mainly through plant wound infection, but also through direct infection from flowering organs, necrotic tissues and epidermis, and the plant is not easy to be infected. Gray mold is most likely to occur when the relative humidity is maintained at about 90% and the temperature is about 18-25℃. When the air humidity is high, the disease develops rapidly, when the air is monotonous, the development is slow, the gray mold is few, the flowerpot is placed too densely, and the greenhouse with poor ventilation occurs seriously. If nitrogen fertilizer is too much, the plant tissue is tender and weak, and the disease is serious. Continuous rain, insufficient light, excessive nitrogen fertilizer, poor soil drainage, continuous cropping for many years are easy to be infected by bacteria, the disease is serious. Gray mold is easy to break out under the condition that weather turns clear and humidity increases after continuous overcast and low temperature. The old leaves of some flowers are more sensitive to gray mold, and the declining leaves and flowers are often the occasions where gray mold bacteria breed in large numbers. A large number of spores fly into the air and cause diseases when they meet suitable temperature and humidity conditions. Spraying water in greenhouses also helps spread germs. Cuttage seedlings, because of the use of film for arch shed, its humidity is very large, shed film if too much condensed water will also aggravate the occurrence of disease. Plants are susceptible to disease in poorly ventilated, shady and humid environments. Usually in winter and spring in the north, the greenhouse temperature is not high enough humidity when the plant disease is heavier.

IV. Prevention and control techniques

Control techniques include variety selection, cultivation techniques, disease prevention and drug protection.

1。variety selection

For example, carnation safflower varieties are more resistant than yellow flower varieties. Under the same conditions, safflower varieties are less susceptible than yellow flower varieties.

2。early resolution

(1) Seed disinfection

To kill fungi attached to the surface of flower seeds, seeds can be soaked in 10% trisodium phosphate solution for 20 minutes and washed with running water for 40 minutes before use. It can also be soaked in warm water at 52℃ for 30 minutes and dried for later use.

(2) Substrate disinfection bacteria mainly winter in the soil, therefore, whether garden or potted, all request the soil is disease-free new soil, and the flowerpot, seed ball disinfection.

(3) To reduce the infection source is to reduce the infection origin, eliminate the diseased flowers, diseased leaves and other residues at any time, and cut off the fallen flowers in time.

(4) The rest of the solution is planted with seed balls and seedlings, and the diseased plants are removed before planting, and 0. 3-0。5% copper sulfate immersion 0. 5 hours, washed and dried before planting.

3。field management

When planting, apply enough base fertilizer to improve plant development and strengthen resistance. Try to apply decomposed organic fertilizer, increase phosphorus and potassium fertilizer, and pay attention to control the amount of nitrogen fertilizer to avoid excessive growth and aggravate diseases, so as to maintain plant health and improve disease resistance. Early disease in time to remove the disease part, not directly piled in the greenhouse or on the garbage heap, should be concentrated for high temperature composting or deep burial. Strengthen the cultivation management of potted flowers, pay attention to ventilation and light transmission, and leave sufficient space between flowerpots. Watering to "see dry see wet", basin soil should not be too wet, avoid ponding. Field should pay attention to ventilation and light transmission between plants, timely drainage after rain. The management process should minimize plant damage, avoid wounds and avoid invasion of germs.

4。Improve environmental conditions and control disease occurrence. Increase indoor illumination, improve host disease resistance. Greenhouse should pay attention to ventilation and light transmission, reduce humidity, potted flowers to avoid placing too dense, watering fertilizer should not be too much, avoid spraying watering, watering is best injected from the edge of the flowerpot, lest the leaf humidity is large and conducive to disease. Avoid rainy days watering, watering stagnation should be ventilated moisture, after the disease control watering, if necessary, to implement the rhizome around the watering. Different flowers should not be mixed in the same greenhouse. Decreasing humidity reduces dew condensation on the roof and leaves of the shed. The greenhouse should be ventilated in time to reduce the humidity to below 80%, especially when the temperature rises on sunny days after continuous overcast. This work should be done in time. Pay attention to operation hygiene to avoid diseases in the management process.

The optimum temperature for gray mold disease is between 20-25℃, and the pathogen stops infection, growth and breeding above 32℃. Using this principle, the development and infection of the pathogen can be controlled by increasing the temperature in protected cultivation. The method has obvious effect in autumn. Usually take late ventilation in the morning, so that the greenhouse and temperature room temperature increased to 31-33℃ between, more than 33℃ start ventilation, if near noon is still above 25℃, can continue ventilation, but the afternoon temperature needs to be maintained at 20-25℃, down to 20℃ must open tuyere, night temperature maintained at 15-17℃, if the method is controlled, can play the goal of preventing gray mold without drugs. 5。At present, there is no specific drug for the prevention and control of this disease, so prevention should be given priority to and the opportunity should be grasped for chemical prevention and control. It can spray foliage, fumigate and dust. (1) Before and at the beginning of the disease, spray with 1:200 Bordeaux mixture once every two weeks. (2) After the disease, cut off the diseased leaves in time and spray chemicals for prevention and control. (3) Chemical fumigation. (4) Spray dust.