Prevention and Control of Grey Mold Disease in Greenhouse Flowers
Let me tell you about the explanation of flowers in the floral clinic, the prevention and control of grey mold disease in greenhouse flowers, and a comprehensive introduction is about to follow.
Grey mold disease is an important disease of greenhouse flowers, mainly affecting the flowers, fruits, and leaves of the plants. It often occurs during the growing season of flowers, especially during the winter and spring greenhouse growing period. If management is relaxed, it is more conducive to the occurrence and spread of the disease, which can cause a large number of flowers and leaves to fall, affect the flowering of the plants, and reduce their ornamental value.
Causal Agent and Conditions: Grey mold disease is caused by the half-known fungal species Botrytis cinerea. The pathogen exists in the form of mycelium, conidia, and sclerotia attached to diseased residues or left in the soil to overwinter. The optimal temperature for the fungus to develop is between 10°C and 32°C, with a minimum of 4°C, and a relative humidity of 90% or higher is required. Due to the suitable spring temperatures and high humidity in the greenhouse, if ventilation is not timely, it becomes the main reason for severe outbreaks. The main symptoms of the disease: The pathogen invades through the stigma hairs, the stomata of the flower peduncle, or wounds, spreads to the fruit peduncle, causing the fruit skin to become greyish-white and water-soaked soft rot. When the humidity is high, a large amount of grey mold layer forms on the fruit surface. Diseased flowers falling on the leaves can easily cause leaf infections, forming large circular spots with grey mold. Rotting flowers and fruits falling on the stem can cause stem rot, and in severe cases, the plant can die. For example, when chrysanthemum leaves are affected, the leaf edges show brown spots, the surface is slightly corrugated with a wheel pattern, the petioles and flower stalks first soften, and then the surface rots. When the leaf of Fuchsia is affected, the diseased leaves show water-soaked spots that gradually turn blackish-brown and rot. Additionally, African daisies and cyclamen are also susceptible to damage.
Control Methods
1. Seed disinfection. To kill fungi attached to the surface of flower seeds, seeds can be soaked in a 10% sodium metaphosphate solution for 20 minutes, then rinsed in running water for 40 minutes before use. They can also be soaked in warm water at 52°C for 30 minutes, then dried before use.
2. Planting in guest soil. The pathogen mainly overwinters in the soil, so whether it is garden planting or pot planting, the soil must be disease-free new soil, and the potting soil, flower pots, and bulbs should be disinfected.
3. Reasonable fertilization. Use decomposed organic fertilizers as much as possible, add phosphorus and potassium fertilizers to improve the plant's resistance to disease, and also pay attention to controlling the amount of nitrogen fertilizer to prevent excessive growth and exacerbate the disease.
4. Greenhouse management. Timely remove diseased leaves, flowers, and fruits, as well as yellow leaves, to keep the greenhouse clean and ensure good ventilation and light. Suppress the fungus with high temperatures in the greenhouse. In the early growing stage and after the onset of the disease, appropriately control watering and release air later. Increase the greenhouse temperature to 33°C, which is not conducive to the production of differentiation spores. Reduce humidity to prevent dew formation on the greenhouse roof and leaf surfaces.
5. Chemical control. In the early stage of the disease, you can use a 45% Topsin M smoke fumigant, or a 15% Fastak fumigant for 3 to 4 hours (250 grams per mu of greenhouse). You can also use a 5% Topsin M dust (1 kilogram per mu of greenhouse) in the evening. Spraying method can use a 65% Dithane Z-78 WP 500 times liquid, spray once every 10 days, and continue for 2 to 4 times (interval of 7 to 10 days). Alternatively, spray 50% Fastak 1000 times liquid or 50% Polyoxin 1000 times liquid at the beginning of the disease, alternating every 7 days, and continuing for 2 to 3 times, all of which can effectively control the occurrence of grey mold disease.
The detailed introduction of the prevention and control of grey mold disease in greenhouse flowers mentioned above, do you understand now?