It's wet and wet in summer. Are the plants at home sick again? We should prescribe the right medicine at this time.

The humid and hot summer is the period of high incidence of plant diseases. If you are not careful, the potted flowers in the family may cause all kinds of diseases. Let's take a look at the common disease identification methods summarized by flower friends for the following three kinds of flowers. If your "baby" is unfortunately hit, then quickly prescribe the right medicine to the case!

Soft rot and black rot of orchids

For orchid farmers, the harm of rot is a thorny problem, not only the symptoms are difficult to identify, but also it is difficult to prevent and cure the disease. The following is a brief talk about the soft rot and black rot that cause orchid rot.

Soft rot

Symptoms of the disease: the disease mainly infects orchid varieties with thicker mesophyll, and mainly harms new leaves on Phalaenopsis, Cartland and other foreign orchids, showing water-stained spots on the leaves, gradually changing from dark green to dark brown. In Chunlan, Sijilan and other Chinese orchids, it is mainly manifested as the appearance of small yellow-brown watery spots on the upper and lower parts of the new buds, and then the disease spots expand rapidly, and the parts or wounds that have been flooded with water soon rot, which can be pulled up gently after decay, or break and lodge, which leads to the name of soft rot. When the disease is serious, the whole leaf turns brown and droops in the form of soft decay. when the mesophyll tissue is rotten, there is a yellowish-brown mucus outflow from the disease, and the mucus has a foul smell.

Disease conditions: orchid soft rot is caused by bacterial infection, which overwinters mainly on the stump of diseased plant tissue, spreads through wind and rain, invades through various minor wounds of orchid plant, and directly uses unclean culture soil, garden soil, etc. excessive application of nitrogen fertilizer in the new bud growth period is easy to cause thin cell wall and induce bacterial invasion. The basin soil is too wet for a long time, resulting in a large number of aerophobic bacteria and harmful microorganisms in the soil, affecting the growth of orchid roots, decreasing resistance and prone to disease; in open-air cultivation, poor ventilation conditions, extensive management, watering with bacteria, or water in the heart leaves of orchid plants after a sharp rise in temperature after summer rain are easy to cause soft rot.

Prevention and control methods:

1. Choose clean culture soil. Alpine humus soil is the most ideal plant material for orchid cultivation. If garden soil, pond mud and so on are used, they should be exposed to high temperature and fungicides are added before use.

two。 Rational fertilization and watering. Conditional can choose clean mountain spring water, river water watering orchid, the water source is not clean need to precipitate to slag, add disinfectant treatment after use. Watering during the high temperature period should be carried out when the temperature is relatively low in the early morning to avoid flooding, let alone use coarse spray or directly pour water into new leaves or buds. With the application of phosphorus and potassium fertilizer, the selection of liquid nitrogen fertilizer was carried out before the new buds germinated to the time when the new buds grew but did not expand the leaves.

3. Chemical control. Orchids on the pot, 3 to 4 days without watering, with 50% Fumishuang 500 times liquid spray 1 time, disinfection and sterilization. After the disease is rescued, the diseased plants should be temporarily isolated from other orchids to avoid infection, and only after returning to normal can they be put together with other orchids. In the onset season, especially after heavy rain, it can be prevented by 4000 times of neophytomycin or agricultural streptomycin sulfate. generally, it is sprayed 2 to 3 times every 5 to 7 days, and the new bud and lower leaves or bulbs are sprayed with fine spray.

Black rot

Symptoms of the disease: black rot mostly occurs in leaves, root bases and growing points. Translucent spots appeared on the leaves of the injured plants, almost all over the leaves, and the disease spots enlarged and affected the whole plant (including the roots). After the adult plants were killed, dark and slightly flooded spots appeared on the leaves or pseudobulbs within 2 to 5 days, and the disease spots later became purple-black and shiny. The disease becomes soft in a warm and humid environment, and water exudates from the diseased leaves. The disease department dries when the environment is dry.

Prevention and treatment: cut off the diseased leaves and damaged false bulbs and destroy them centrally. The used knives and scissors can be disinfected and sterilized with 75% alcohol. Avoid watering and keep ventilated and transparent when watering.

Rose black spot

Rose black spot is the most common destructive disease of rose, which can not only harm rose, but also harm roses, roses and other flowers and plants. In the later stage of occurrence, drug control is also difficult to control its spread, therefore, early prevention and treatment is very important.

Disease symptoms: the disease mainly harms leaves, but also twigs and flowers. When the disease occurs, irregular black spots appear on the leaf surface or on the edge of the leaf, which makes the color of the adjacent mesophyll tissue change from green to yellow, and in severe cases, the whole leaf turns yellow. Another symptom is that there are dark brown near-round or irregular wheel spots on the leaves, which produce black dots, the diseased leaves are easy to fall off, and only bald branches are left, affecting the ornamental effect and the number of flowers.

Disease condition: rose black spot is a kind of fungal disease. When the air temperature rises to about 25 ℃, the air humidity is close to saturation and muggy weather, the disease is the most serious, and the disease spreads most rapidly in the plum rain season, especially in the two peak periods from May to June and from August to September. Black spot pathogen often winters in fallen leaves, branches, or soil. When humidity and temperature are suitable in March and April of the following year, it spreads with the help of Rain Water, wind, or soil splashed during watering. Rainy, foggy, dewy weather spreads even faster. If the afternoon watering is too late, the leaf surface is not dry, it can also promote the occurrence of the disease. In addition, overdense planting or poor ventilation are also the main causes of the disease.

Prevention and control methods:

1. Disease resistant varieties were selected. There are great differences in resistance to black spot among different varieties, and the resistance of rattan rose is stronger. Among the cultivated varieties, Isbel, White Knight, Xinghua Village, Golden Phoenix, Star, Rihui and other varieties have strong disease resistance; Huang Heping, Nanhai and other varieties are susceptible to disease.

two。 Strengthen cultivation management. Remove the diseased leaves and diseased branches from the garden and destroy them centrally; prune the diseased branches and overgrown branches in time to create a ventilated environment. Do not touch the diseased leaves casually during pruning to prevent artificial transmission, and do not pour water on the leaves. It is best to pour them into the soil to prevent germs from spreading with the water.

3. Match the cultivated soil. The cultivated soil should be aerated, the potted rose should be replaced with new soil in time, and trace element fertilizers such as 1% zinc sulfate or 0.2% potassium dihydrogen phosphate and 0.1% sodium tetraborate should be applied to enhance the disease resistance of the plant.

4. Chemical control. In early spring, after mixing 1% Fumetarsine with river sand at 1:99, it is spread on the surface of the basin soil to isolate or kill the germs on the fallen leaves on the ground. Spray 75% chlorothalonil wettable powder 1000 times or 70% methyl topiramate 1000 times at the beginning of germination, and then spray every 15 days.

Botrytis cinerea and bacterial soft rot of cyclamen

Grey mold disease

Disease symptoms: mainly harmful to leaves and flowers. Petal damage will produce waterlogged spots with a diameter of 1 to 2 mm, which will soon expand and become brown and rotten; occur in the pedicel, brown soft rot, the disease site will fold, affecting seed maturity; when the leaf is injured, brown soft disease spots often occur from the leaf edge, there are wheel wrinkles on the surface, and then expand to the whole leaf, wet gray mold layer, and then become yellowish gray mold.

Disease conditions: indoor humidity is too high and poor ventilation, plant placement is too dense, too much nitrogen fertilizer and so on.

Prevention and treatment: avoid excessive humidity, timely removal of diseased leaves to reduce transmission of infection. Spraying 200 Bordeaux solution or 65% zinc wettable powder 500 times at the initial stage of the disease can control and reduce the harm of Botrytis cinerea.

Bacterial soft rot

Symptoms of the disease: it mainly harms the petiole and pedicel of the plant, especially it is easy to soften and spread up and down near the cultured soil, causing the corm to rot.

Disease conditions: it is easy to occur in the growing period from July to August, which is mainly caused by bacteria in the soil, and it is more likely to occur when the temperature is high and the basin soil temperature is high.

Prevention and treatment: 0.5% formalin is used for soil disinfection, which can inhibit the occurrence of the disease. In addition, in summer to maintain ventilation, avoid watering too wet, when the disease with crude streptomycin 100 to 200 mg / L spray.