Prevention of "five pests" of flowers in greenhouse in winter

In recent years, low-cost plastic greenhouses are widely used by flower producers. However, due to the low temperature and soil temperature in the greenhouse in winter, the greenhouse is closed for a long time, coupled with poor management, it is prone to varying degrees of freezing, dampness, wind, gas and disease, which will affect the growth of flowers and cause the death of flowers, which should be avoided.

First, freezing damage to the north of the Yangtze River, the winter temperature is relatively low, especially from January to late February, the low temperature below 0 ℃ will appear in the plastic greenhouse before sunrise, and freezing damage will often occur. Therefore, for Milan, primroses, melon and leaf chrysanthemum and other cold-resistant flowers, in the evening should be set in the greenhouse and covered with grass curtains. The flowers planted on the ground can also be covered with plastic film to improve the soil temperature. Mulching can not only increase the soil temperature by more than 1 ℃, but also increase the amount of organic fertilizer and phosphorus and potassium fertilizer, which can not only improve the soil aggregate structure, increase the soil temperature, provide nutrients for flowers, but also enhance the freezing resistance of flowers.

Second, wet damage during the period of more rain and snow in winter, if the greenhouse is sealed for a long time, it is very easy to produce wet damage. High soil water content will not only reduce the soil temperature, but also cause anoxia in the soil, which seriously affect the growth and development of flower roots. Therefore, a good drainage ditch should be opened around the greenhouse, so that the open water can be discharged quickly, the water in the underlying layer can be leached, and the soil moisture can be reduced. It is also reported that the application of plant ash on the basin and the ground can not only absorb heat and increase temperature, absorb moisture and reduce humidity, but also increase the content of potash fertilizer in the soil. It is necessary to tighten the greenhouse film and strictly prevent the roof from leaking when it rains and snows.

Third, the main cause of wind damage is that the pressing line of the plastic film can not withstand the strong wind, so that the plastic film is blown over or damaged, and the flowers are destroyed at once. Therefore, the pressing line of the shed film must use No. 8 lead wire or a nylon rope and an No. 8 lead wire, and try not to use nylon rope alone. Fasten the lead wire and nylon rope from both sides of the greenhouse.

Fourth, air damage plastic greenhouse is easy to accumulate harmful gases under airtight conditions, such as ammonia, carbon monoxide, sulfur dioxide and so on. Ammonia is mainly produced in the decomposition process of immature organic fertilizer, and a large amount of ammonia will be produced by topdressing chemical fertilizer. Carbon monoxide and sulfur dioxide are the gases released when coal is burned when the shed is heated by an open fire. Therefore, the application of organic fertilizer must be fully mature, try to use chemical fertilizer topdressing as little as possible, if not, should be timely covered with soil. In sunny and windless weather, it should be ventilated and discharged harmful gases from the shed. Try not to use open fire to heat up in the shed.

Fifth, although the humidity in the plastic greenhouse of diseases and insect pests is relatively high, it is easy to cause the occurrence and development of diseases, but because the spread of wind and rain to bacteria is reduced in the greenhouse, and the temperature and humidity in the greenhouse can be artificially controlled, it also has a favorable side.

1. Anthrax camellia, Milan, evergreen, orchids, orchids, roses and other flowers are vulnerable to it. At the initial stage of the disease, 75% chlorothalonil can be sprayed, or 70% methyl topiramate 1000 times. If you are seriously ill, you should spray every 7 to 10 days, two or three times in a row.

2. Powdery mildew occurred seriously in the environment of high temperature and humidity, poor ventilation and poor light conditions, especially Chrysanthemum morifolium. Can be sprayed with 1 ∶ 1 ∶ 140 equivalent Bordeaux solution, 25% PUBN wettable powder 1000 times.

3. The main insect pests are aphids, which are easy to concentrate on the tender leaf buds, leaves and buds of flowers. After occurrence, it can be sprayed with 5% fipronil 800x liquid, or 2.5% enemy kill 1500 times liquid, or 25% kungfu EC 1200 times liquid, the killing rate can reach more than 95%.