Five methods for prevention and control of Botrytis cinerea

In the previous article, the editor introduced the feeding method of poinsettia, in fact, a variety is more prone to gray mold. Botrytis cinerea for poinsettia will not only affect the appearance, serious, poinsettia spots will be dry, completely lose the ornamental value. The editor will introduce to you several methods to prevent and cure Botrytis cinerea.

Poinsettia

1. Select excellent disease-resistant varieties.

2. Strengthen cultivation management, increase phosphorus and potassium fertilizer, promote plant health and enhance disease resistance, pay attention to plant shaping and pruning, remove fallen leaves in time, and strengthen ventilation and light transmission.

3. Regulate the small environment and restrain the occurrence and spread of diseases and insect pests. It is generally used to increase temperature and reduce humidity to control the development and infection of bacteria. Maintain air circulation, reduce environmental humidity, plants should not be placed too dense, family potted plants can be moved to the balcony, watering can be controlled after illness to avoid foliar water. Keep the temperature above 16 ℃ as much as possible, especially during flowering.

4. Once diseased leaves and branches are found, the diseased leaves and branches should be removed and burned in a concentrated way to cut off the source of infection.

5. Chemical control: spray 1 ∶ 1 ∶ Bordeaux solution two or three times in spring to protect new leaves and buds and prevent disease. During the onset of the disease, 65% Dysen zinc 500x solution, 50% methyl topiramate wettable powder 800x to 1000 fold solution or 75% chlorothalonil wettable powder 600x solution can be sprayed. Other agents include prohydantoin, Yili, Botrytis cinerea Suke, Scarlett and so on. The medicine should be used thoroughly, repeatedly, and several drugs should be used in turn. Fumigant can also be used if sealed at room temperature in winter, and the effect is better.

The method of preventing and curing Botrytis cinerea

Botrytis cinerea is the most common disease in poinsettia cultivation, which may occur throughout the growing season in the greenhouse, and all parts of the plant may be infected. Because it mainly occurs in winter, when poinsettia blossoms, once encountered rainy, wet weather, often out of control. Botrytis cinerea is mainly harmful to inflorescences, bracts, flower branches and young shoots of poinsettia, and young plants sometimes get sick on the surface of the cultivation medium. Under the condition of higher temperature, gray hairy mold will be formed on this decaying tissue. Black rot occurs on mature branches, and this black rot develops around the stem, causing the leaves above the damaged surface to wilt. When infecting bracts, red bracts become lavender when they become infected. First, the law of disease generally starts from the inflorescence with water-immersed spots, then gradually expands, and the diseased tissue turns brown to black and decays, and a layer of gray to grayish-brown mold is formed on the later surface in a humid environment. The spot is covered with a layer of pathogenic conidia, and the pathogen continues to spread to the bracts, producing water-immersed discoloration spots at the initial stage, and then gradually expanding into irregular shape. After being infected, the floral organ also turns brown, decays and falls off. The pathogen extends to the branches and produces yellowish-brown to brown spots on the branches. In the later stage, the disease spot is obviously dark brown in the downward depression, and in severe cases, the disease spot is dry, which completely loses its ornamental value. The pathogen lives on dead plant tissue or other organic matter, is easy to grow and develop on succulent, aging and injured tissue, has a wide range of parasites, and is easy to occur at low temperature and high humidity (relative humidity 90% to 100%). If the greenhouse is too humid, cold, and lack of light, after a day or two, the pathogen produces a large number of spores free in the air and begins to infect plant tissue. Under moist conditions, the disease parts are grayish brown mildew layer. The disease mostly occurs in cold and humid weather, and the optimum development temperature of the pathogen is about 20 ℃. The disease is serious in the air, and the disease can be spread by wind and rain, especially when it is sunny after rain.

Symptoms and control methods of Botrytis cinerea

Symptoms and harm: the disease is common, when the disease is serious, it causes flower withering, plant withering and loss of commercial value. The disease also harms other poinsettias. The disease is mainly harmful to flower crying, leaves and tender shoots. The disease first occurs in the injured, residual and necrotic tissue of leaves, stems and flowers. The leaf edge of the diseased leaf appeared brown water-stained plaques, which expanded inward and showed brown wet rot when the humidity was high. There are waterlogged brown patches on the petals of the flower organ, which expand inward, and the flowers rot and scorch when the conditions are suitable. The tender shoots appeared long waterlogged brown patches, and the branches were broken when the disease was serious. Under the condition of high humidity, the gray mildew layer can be produced in the disease part.

Pathogen: the disease is a fungal disease caused by Botrytis cinerea. Characteristics of the disease: the pathogen overwintered on the diseased body; it was spread by airflow, wind and rain. The disease is easy to occur under the conditions of cold, high humidity and many wounds. The disease is usually serious in early spring or late autumn. Disease control methods of double-petal varieties: 1) cultivation techniques to prevent disease: planting density should be appropriate to facilitate ventilation and light transmission, reduce humidity; timely remove old fallen flowers and withered leaves, reduce the source of reproduction; good control of greenhouse humidity is a key measure to prevent the disease, humidity below 80% can inhibit the occurrence of the disease. Drainage in time after rain in the field. 2) Pharmaceutical protection: do a good job of prediction and timely prevention. The measuring and forecasting work is mainly based on the temperature and humidity of the weather.

Therapeutic fungicides: 50% carbendazide, 16% isobarbazide. Prochloraz, Kaiser

Protective fungicide: isobarbazide, Cobo

Related topic: poinsettia cultivation Daquan