Control methods of poinsettia disease

1. Grey mold disease

Symptoms: Botrytis cinerea often occurs during winter flowering. Once encounter rainy, no light weather, Botrytis cinerea will become more and more serious, leaves, branches, inflorescence will appear brown spots, with the aggravation of the disease spread the whole plant.

Prevention and control methods: in winter, it is necessary to strengthen aquaculture management, which can increase indoor temperature and enhance light. Must change the plant to the ventilated place, bask in the sun more, can play the effective prevention. If the condition is serious, Bordeaux liquid can be sprayed to treat it.

two。 Leaf spot disease

Symptoms: leaf spot disease is more serious in summer, and it often starts from the old leaves. In the early stage, irregular brown spots were produced on the leaves, and then began to spread rapidly, and many disease spots aggregated into large disease spots. In severe cases, it will make the leaves twist and dry up.

Control methods: often cut off old and withered leaves, keep them clean, spray chemicals when the disease is serious, choose 1000-fold solution of chlorothalonil, spray once every 5-7 days, and improve after 3-5 days.

3. Root rot disease

Symptoms: root rot often occurs in hot weather, but it may also be caused by soil and watering problems. It is difficult to find near the ground at the beginning, as the disease spot spreads upward, the plant will gradually wither, and in the later stage, the plant will be unable to absorb water and die.

Prevention and control methods: usually change the soil, loosen the soil, in addition, in the process of breeding, disinfectant can be used to irrigate the root once a month to inhibit the growth of fungi. When rotting roots, the rotten parts should be cut off and replanted.

Diseases and control methods of poinsettia

Poinsettia diseases can be divided into four categories: fungal diseases, bacterial diseases, viruses and protoplast diseases. First, the pathogen of fungal disease is fungus, which is infected by wound, natural orifice such as stomata or surface contact. The common diseases are as follows: (1) Rhizome rot: mainly caused by the following fungal infections: 1. ① symptoms of root rot caused by Rhizoctonia sclerotiorum are most likely to be infected when the stem is in contact with the surface of the medium, especially when the stem is injured or fertilizer and salt accumulates on the surface of the medium. At first, brown but dry patches appear at the infected site, and these brown plaques gradually expand as the fungus grows, even reaching the roots. This kind of fungus is easily carried by substrates and susceptible plants and spreads easily with water. In addition, although they do not have airbag spores, they can also be spread by infected dust. ② control measures to remove infected plants in time, do not litter infected branches and leaves at will. The effect of filling with fungicide is better. The commonly used medicaments are Yili, Ruidotoxin, Cleary and so on. two。 The main ① symptom of root rot caused by Pythium is root fester. When the root is infected, the root tip and cortex usually appear brown rot. The pathogen entered the stem from bottom to top and developed to the stem tip. The whole stem gradually became watery, the color from brown to black, and then the rotting root cortex fell off. Susceptible plants usually do not develop well, the lower leaves turn yellow and fall off, and in severe cases, the whole plant will die. Germs spread easily through water. The disease is easy to occur in the case of poor drainage of the matrix or too much water in the matrix. There is a characteristic of root rot caused by Pythium, that is, although the susceptible pathogen of some infected plants has invaded in the early stage of cultivation, the disease is often covered up because of the rapid root development, and when the plant is about to blossom and the root develops slowly, the symptoms begin to appear obviously, causing the plant to turn yellow, wither and even die. The effect of fungicide application on ② control measures is better. The commonly used fungicides are: Ruidusu, Banrot, Truban and so on. 3. ① symptom disease caused by Phytophthora infestans can endanger all parts of the plant, including leaves, stems, crowns and roots. There are gray to brown or black ulcerated plaques on the stem, and the medullary stomata turn brown. At first, the leaves appeared small brown or yellowish brown spots, then gradually expanded under suitable conditions, and finally the whole leaf was brown or black. Root rot and bract decay can also occur. With the aggravation of the disease, the whole plant wilted and died. ② control measures such as high temperature and excessive irrigation can easily lead to the occurrence of this disease, so the temperature should be reduced as much as possible to avoid excessive soil moisture when planting in summer. The application of fungicides such as Trichoderma, Banrot, Truban and other fungicides is helpful to control the disease.

Disease of poinsettia and its control measures

Botrytis cinerea

Botrytis cinerea occurs in winter, that is, the blooming season, once encountered rainy, wet and sunless weather gray mold is out of control. Brown spots appear on leaves, branches and inflorescences, which spread throughout the plant with the aggravation of the disease.

Therefore, especially in winter, it is necessary to strengthen maintenance and management, improve indoor temperature, enhance light transmittance and reduce humidity. Once the diseased plant is found, immediately move the plant to the ventilated place and put it in the sun, which can play an effective control effect. In addition, when the disease is serious, Bordeaux liquid can be sprayed for treatment.

Poinsettia root rot

Root rot usually occurs in high temperature season, but it can also be induced by soil, watering and other reasons. Light brown spots on the roots can be seen in the infected plants, but it is difficult to find symptoms on the ground at the initial stage. With the aggravation of the disease, the disease spot spread upward, the plant will gradually wither, and in the later stage, the plant will die because the root is unable to absorb water and the plant is short of water.

Strengthen maintenance at ordinary times, change the soil in time, and often loosen the soil to ensure that there is sufficient oxygen for root breathing. In addition, in the process of maintenance, disinfectants can be used to irrigate roots once a month to inhibit fungal growth.

When rotting the root, remove the plant, cut off the rotten part, replant it, and throw it away if the rotten root is serious.

Poinsettia leaf spot

It mainly occurs in spring and summer, and most of the disease spots begin to occur in the old leaves. In the early stage, irregular disease spots appeared in the leaves, which expanded and spread, causing the leaves to twist and dry up.

Diseased spots on the leaves were removed and discarded in time. Usually clean up the dead leaves and keep the surface of the basin soil clean.

When the disease is serious, you can choose chlorothalonil 1000 times solution, spray once every 5 to 7 days, and improve in 3 to 5 days.