Common diseases and insect pests of orchids

Orchid diseases and insect pests are important factors affecting orchid growth. How much do you know about common orchid diseases and insect pests? Let's take a look at the common diseases and pests of orchids that I carefully recommend for everyone, hoping to help you.

Common diseases and pests of orchids: dead shoots of orchids.

The tip of orchid is scorched, which is one of the common diseases. It not only damages the integrity of orchid leaves, affects the ornamental value and economic value, but also seriously affects the healthy growth of orchid plants and even endangers their lives. After years of practice and exploration, it is considered that the tip scorching of orchids is caused by physiological diseases and infectious diseases. Most of them are caused by physiological diseases. Now described as follows:

First of all, Langen was born with poor growth.

It can be said that whenever the top of orchid plants is burnt, there will be different degrees of root rot. There are many reasons for poor root growth.

1, water stain:

Mainly, the orchid flowerpot is delicate in texture and slow in water evaporation; The culture medium is not rough enough and the drainage performance is low; Too much water. Orchids? Love rain and fear waterlogging? ,? Happy to moisturize but afraid of getting wet? . But don't let go Run? The word is understood as moist and moist, and orchids are poured into mud like paddy fields. It should be sheltered from the rain in Mao Mao, and it is advisable to water the basin two or three days after the soil is dry. Orchid bonsai should use rough clay pots. Try to use a special blue flowerpot with high pipes and high feet, porous walls and a big hole in the bottom. In the case of delicate porcelain pots and teapot, it is best to drill as many holes as possible. On the other hand, the bottom of the basin must not be blocked with tiles, but must be overhead. The culture medium must be as rough as possible, and the local mountain mud should be mixed with rough plant materials such as broken bricks and burnt soil, or disinfected snake sawdust and cedar sawdust to enhance air permeability and hydrophobicity.

2, freezing injury:

Orchids are shade plants, which are not tolerant to low temperature and frost. When the temperature is below zero, most orchids have different degrees of freezing damage. If the root tip is frostbitten, it will dry up gradually and lose the ability to absorb water and nutrients. In the next spring, the temperature will rise, the light will increase, and the tip will be scorched without supply. Even the new buds sprouting in late spring can't supply the consumption of new bud development, because the plants can't get the supply, which leads to the slow growth of the roots of new buds and the scorching of the top.

There is another situation, that is, simple greenhouses and plastic films are covered in situ to prevent freezing, because moisture can not be discharged and absorbed, and the water vapor in the films drips back on the orchid leaves to freeze, as if it had been scalded by boiling water. Slightly frozen, although it can be recovered, a large area of tail burning gradually appeared in late spring and early summer. Therefore, for simple greenhouses and in-situ film mulching, moisture-absorbing cloth, blankets, sacks, grass curtains and so on. It should be hung in the greenhouse.

3, fertilizer damage:

? Orchids like fat and fear turbidity? . Orchid fertilization needs not only low concentration and long interval, but also low application amount. Too thick and dense fertilization is easy to clean and damage the roots of orchids, leading to scorching of the tip.

On the other hand, planting orchids generally does not require base fertilizer; If necessary, the proportion should be less, generally not more than 1%. Organic fertilizer without fermentation, decomposition and disinfection shall not be used as base fertilizer for planting orchids to prevent them from fermenting in pots and scalding their roots.

4, high temperature hazards:

In the hot season of summer and autumn, in greenhouses and plastic greenhouses, under the radiation of the scorching sun, the temperature is as high as 30 degrees or even 40 degrees, which is very sultry. As soon as the limited water in the site rises, it is consumed and cannot reach the tip of the leaf, resulting in the tail, edge and tip of the leaf being scorched.

In another case, the root tips of orchids planted in thin tube pots are close to the wall of the pots, and the hot and hot wall of the pots will also burn the root tips, causing the tips to burn. Therefore, shading, ventilation, water spraying and fog cooling should be strengthened in high temperature season, and the basin wall should be moist.

5, acid damage:

For substrates that have not been changed for more than two years, because of frequent application of acidic fertilizers and other factors, the substrate is too acidic, which will also cause root rot. The solution is:

(1) replacing seedlings with new substrates;

(2) Pour into 3000 times of liquid white alkali water for neutralization at one time.

6, the harm of hormones:

Some people, in order to dwarf orchids, impose? What's the effect? This kind of dwarfing agent, because of its high toxicity and long residual period, makes the roots black and rot, resulting in the loss of root function, insufficient supply of leaves, and scorched tips until the whole plant dies.

7, the harm of lack of elements:

Some people tend to increase the proportion of nitrogen fertilizer in order to make the leaves dark green and germinate more, so that the three elements of fertilizer lose their relative balance. The most common symptoms are potassium deficiency, terminal leaf margin and tip scorching. So don't use too much nitrogen fertilizer, pay attention to supplement potassium dihydrogen phosphate outside the roots, or sprinkle some on the basin surface? Reed ash? .

8. Diseases:

The most common root diseases are root rot, black rot, soft rot and bacterial wilt. It involves roots, leading to the loss of root function, leading to the burning of leaf tips and the death of the whole plant. Therefore, whenever a new bud develops slowly or has no leaves, it is necessary to explore the roots. If problems are found, seedlings should be raised, washed, disinfected and replanted.

It is important to prevent this disease. Generally speaking, the culture medium should not be too wet, and strive for partial nitrogen fertilizer. After the temperature rises in warm spring, use 800 ~ 1000 times liquid? Dixon. Watering the roots once every ten days, twice and once every quarter can effectively prevent it.

Second, abnormal leaf growth.

1. Physiologically, there are reasons for biased application of nitrogen fertilizer, excessive young leaves and decreased stress resistance; There are fertilizer injuries caused by spraying fertilizer, too high concentration, too large application amount and clogging the tip of the blade; There is dry coke caused by low air humidity; There are frostbite caused by heat preservation in winter, water vapor deposition at the tip of the blade, and freezing at low temperature; Damage caused by long-term contact between the tip of the blade and the basin wall and culture medium; There are lesions caused by potassium deficiency. It should be avoided according to the cause. After spraying fertilizer for eight hours, it is better to suck clean water to wash off the fertilizer, which is more thorough.

2. Infectious diseases:

① scorched tail disease: it is characterized by round or irregular brown spots after infection, which sink slightly and gradually turn brown and wither.

(2) Rust: The characteristic of the disease is that at the early stage of the disease, many iron-brown protrusions will bulge on the back of the leaves, similar to sesame seeds. When the spots break, their spores will fly with the wind and spread around.

(3) Iron cannon disease: the disease is characterized by the appearance of diseased spots at the end of leaves from the leaf edge; Its shape grew from small to large until it was closely connected into pieces, and its color changed from yellow to brown, and finally became dark brown.

The prevention and control measures are to avoid partial application of nitrogen fertilizer; It needs to be planted too densely, and orchids should not be displayed too crowded; Once the disease occurs, the infected site should be removed in time (one or two centimeters should be cut more), and the focus should be cauterized; Chemical control should pay attention to foliar spraying, requiring spraying three times every other day, which will completely control the disease. What are the effective drugs to prevent and treat it? Erie? 1000 times liquid; ? Where's Yi? 500 times liquid; ? Big 45? 500 times liquid; ? So fast and clean? 80O times liquid; ? Antiviral alum? 500 times the liquid.

Third, how to distinguish between physiological diseases and infectious diseases

The scorched parts of physiological diseases have the same color and no spots, and the spots on the back of leaves are not mildewed and released under wet conditions; Disseminated disease started as a point and gradually expanded into pieces, resulting in overall scorching. The color of the spots changed from light to dark, and finally turned black. Under humid conditions, mist will be released.

Common Diseases and Pests of Orchids: Orchid Rot

For orchids, rot is very serious and spreads quickly. Orchid rot mainly includes soft rot and black rot.

In the early stage of soft rot, tiny brown water stains appeared on the leaves, and then expanded into black wet spots. At this time, the spots are easy to break and smelly liquid flows out. After that, the orchid plants will rot quickly. Generally, this disease is prone to occur in rainy and humid seasons above 30℃.

Black rot is a fungal disease, which mostly occurs in leaves, roots and growing points. At first, translucent spots appeared in the diseased area, which gradually expanded, and the tissue turned black and gradually rotted. When it begins to appear on roots or underground stems, it should attract attention. If it is not prevented, it will soon spread from the root system to the whole underground stem until the plants are completely destroyed. In a very short time, the disease can make the roots of orchids turn black and the leaves turn black and rot.

Prevention and control methods: After the orchid is infected with rot, turn over the pots and change the soil in time, cut off all tissues in the affected area and burn them centrally. Then clean the disinfection incision with clear water, coat it with sulfur powder, dry it in a cool and ventilated place, and put it on the pots after the incision is dry. Do not water or spray water for 3 ~ 4 days after taking the basin, and use 50% thiram and 500 times water to make a solution and spray it once. The planting environment should be strengthened with ventilation and lighting. After the rescue, the diseased plants should be temporarily isolated from other orchids to avoid infection. When it grows normally and is not contagious, it can be put together with other orchids.

Common diseases and pests of orchids: black spot of orchids

What kind of orchid is this? See Ye Sheng see flowers? Plants. When orchids are infected with black spot disease, the best radical cure is to remove the diseased leaves, but this will reduce the ornamental value and economic value of orchids (especially precious varieties). The following three methods can effectively cure orchid black spot disease without removing diseased leaves.

After discovering that orchids suffer from black spot disease by gentian violet method, we should immediately wipe the affected area with gentian violet (the smear area is slightly larger than the diseased spot), and the plaque will no longer expand, and it will heal within a few days, so that the leaves can be preserved. It is equally effective to replace gentian violet with potassium permanganate saturated solution.

Spraying vinegar on the leaves of flowers can eliminate black spot, powdery mildew and leaf spot, and also prevent the yellowing of camellia and azalea.

The cooking method is to soak leek leaves in clear water for 24 hours, and the ratio of water to leek is generally 1: 10. Watering flowers soaked in leeks can prevent black spot and powdery mildew, and can alleviate diseases for infected flowers. Spraying water soaked in leeks on the leaves of diseased flowers can also cure diseases.

Orchid planting method

The time of ramet propagation is what we usually call dividing pots. Generally, orchids that grow too densely are divided into multiple pots. Ramet propagation is very common in orchid cultivation, especially when it is cultivated in a small amount at home. Generally speaking, orchids can't be divided into plants in the vigorous growth season, and the more suitable season is the dormant period of orchids, that is, before the new buds are unearthed in March and April, or after the growth of orchids stops in 9- 10.

The specific method of dividing plants When dividing plants, first put the five fingers of the left hand into the orchid seedlings, hold the pot soil, turn the pot upside down with the right hand, and then pat it around the pot to separate it from the pot soil. Then grab the hole in the bottom of the pot with your right hand, so that you can separate the soil from the orchid plants. Care should be taken not to crack the soil lump to ensure that the orchid root system is not broken. Then, we should pat the mound carefully, and gradually photograph the old soil and separate it. Cut off dead leaves, rotten buds, rotten roots, etc. Finally, from the larger plants, find out the small plants that are far away from pseudobulb, find the places that are easy to loosen, cut them with scissors, and coat them with a small amount of carbon powder and sulfur powder, which can effectively prevent the wound from rotting. It should be noted that there should be at least 3 pseudobulb in each part after cutting.

The choice of planting flowerpots should be appropriate, and different specifications of plastic pots, peat pots and porcelain pots can be selected according to the size of orchid plants. However, it should be noted that it is best to use broken bricks at the bottom of the flowerpot, which generally accounts for 1/3 of the height of the flowerpot, which is beneficial to ventilation, water absorption and water retention.

Configuration of culture medium This time we introduce a new culture soil formula, which is different from the garden soil formula introduced in previous experience. This recipe is very suitable for orchids It is a mixture of coconut shell fragments, sterilized bark fragments and volcanic rock fragments (perlite we introduced before). Of course, organic fertilizer can also be added in moderation. If the ramets are small, you can add high-quality water moss (aquatic plants), because water moss is elastic, easy to absorb water and fertilizer, and plays a role in heat preservation.

In the third step of pot culture, a pot with broken bricks as the bottom was added, and the culture soil prepared in the fourth step was added. First, add a half-basin-deep substrate and compact the added substrate by hand. It should be noted that the soil in the center of the basin is preferably slightly higher than that in the surrounding basin. Place the divided seedlings in the center of the pot (there can be more than one, depending on the size of the pot), and then add the culture soil. When it is added to the roots of orchids, gently lift the seedlings upward, so that the roots of orchids fully extend in the basin, and the pores of the roots are filled with soil. Finally, the culture medium is compacted, and it is best to spread a layer of gravel or ceramsite on the culture medium, water it and put it in a cool place.

The planted orchids will enter the slow seedling stage after being planted in the upper pot. Due to the water demand and physiological changes in the seedling stage, we should pay attention not to have too much light during this period, and at the same time keep the culture soil moist. We can ensure the humidity and reduce the temperature by foliar spraying, and the seedlings will enter the normal growth stage around 1 week.

Watering management of orchids orchids are drought-tolerant plants. Excessive watering will affect root respiration and cause root rot. The main principle of watering is to master flexibly according to the weather, temperature and the size of blue plants. Usually wait until the soil is dry before watering, right? If you don't do it, you will fall completely. . If it is a blue seedling, the drought tolerance is relatively poor. So water it often. But you shouldn't water it too much. If orchids bloom, you should water them less often.

Fertilization management of orchids generally adds nitrogen fertilizer in the growth period, which can promote the rapid growth of orchids, strong plants and dark green leaves. Phosphate fertilizer can promote the growth of roots and is also beneficial to flowering, so it should be supplemented during flowering. Generally, orchids need more potassium fertilizer when they grow into plants. It should be noted that fertilization must be combined with watering, preferably watering after fertilization, or spraying foliar fertilizer to ensure the vigorous growth of orchids.

The main diseases of orchids are anthracnose and leaf spot. The main preventive measures of anthrax are cutting off diseased leaves and strengthening ventilation. 70% thiophanate-methyl wettable powder can be sprayed 800 times as a precaution. Control of leaf spot with 800 times solution of 75% chlorothalonil wettable powder. The main pests are scale insects and snails, which are mainly observed in time and removed in time.