Diseases in plants | What are they, types that exist and how to fight them

Diseases in plants | What are they, types that exist and how to fight them
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The diseases in plants are a type of response with cells and plant tissues to certain environmental factors or to pathogenic microorganisms. They produce a certain change in the function, in the form or in the structure of the plant. If not treated in time, these diseases could lead to partial disability, even death.

Depending on the type of tissue and cell that is affected, the biological function of the plant could be nullified. For example, if the infection occurs in the roots, it could happen that they rot and the plant would not be able to absorb water or nutrients from the ground. In the end, he would die.

Some infections attack the leaves, which interferes with photosynthesis.

It could also affect fruits and flowers, interfering with reproduction.

The majority of the cells of the plants that are infected end up dying. However, there are certain exceptions, such as in the case of crown gall, where the cells will divide more quickly, or even enlarge, which will result in amorphous and abnormal tissues.

The diseases in plants are caused by 3 agents: Fungi, bacteria, and viruses.

It is estimated that 95% of these diseases are caused by fungi, although it is advisable not to neglect this remaining 5% that refers to bacterial or viral infections.

The diseases caused by fungi are usually easy to fight, and that is that you just have to use an appropriate fungicide. However, the thing changes if we have an infection by bacteria or by a virus. In this case, there is no product that is considered 100% effective, so it is very important to establish prevention strategies.

Types of diseases in plants

To classify the different types of plant diseases with more success, we have classified them according to these two major groups:

Diseases of indoor plantsDiseases in plants

Brotitis: The fungus parotitis (also known as gray mold ), is an agent that will produce brown lesions, also generating a gray mold in the area of buds, leaves and even flowers. It is more lethal in young and tender plants.

The infestation will occur through pruning cuts, wounds or cracks. For example, if recently the garden has had to face a hail, it will be crucial to start applying an antibiotics treatment to avoid an infection from wounds produced by hail.

Root rot: Many fungi cause this problem, but the most common are Fusarium oxysporium, Rhizoctonia solani, Pythium spp and Phytophthora spp.

The first symptom of this disease of the plants will be manifested in the leaves; these will turn yellow, reaching a point where they will wither and turn brown. The disease will progress until the roots and base of the stem rot.

There are chemical treatments against root rot that are applied around the neck of the plant, but they are not usually very effective.

Powdery Mildew: The powdery mildew is caused by fungi of various genera, how Uncinula spp, Sphaerotheca spp, Erysiphe spp, among many others.. It can be given both in outdoor plants, as in indoor plants. Its identification is not always too easy since it appears as white dust that seems to be only that, dust. However, when we try to shake it we will not be able to.

In the event that the disease continues, we will discover that the spots will unite, becoming larger. All this will cause the attacked parts to dry and fall.

Some of the alternatives that are proposed against powdery mildew are systemic fungicides and sulfur powder.

Bold: The bold is one of the diseases of the most dangerous plants. It is produced from insects like woodlice, aphids, and whiteflies. When these organisms reach the leaves, they use their beak to stick it in the Mimas and extract a liquid from which they will feed. Then they will excrete a substance with a good sugar base, which is what the Negrilla mushroom will use to be able to proliferate.

This disease can be identified as a dry powder of black color. Although it is true that the damage is practically aesthetic, it can also affect the functions of the plant.

The best way to avoid Blight in plants is to use a system to prevent previous insects from reaching them.

Foliate Spots: Species of fungi such as Cercospora spp., Coniothyrium spp or Cercospora spp. Are those that produce these characteristic spots. The very affected leaves cannot be treated, so we will not have to remove them manually. Once they have been removed, it will be a matter of using a systemic fungicide and repeating the treatment approximately every two weeks.

Anthracnose The Anthracnose is a disease in plants that are identified by the presence of dark lesions and bounded on the leaves and young stems. These areas will dry, how a burn is treated.

Leaves affected by this type of diseases of indoor plants must be removed. The application of fungicides only makes sense if the spots have not yet appeared; If that were so, unfortunately, there would not be much we could do to save it.

Alternariosis: The first symptom that identifies the presence of this disease in plants is the presence of brown or black spots that, in certain cases, may be surrounded by cylindrical aureoles. The spots will grow progressively, and at the same time, they have the ability to dry the leaves.

It is usually a very common disorder in those plants that do not feed correctly. The most logical way to avoid Alternaria is to use preventive treatments.

Sclerotinia: This disease directly affects the stem of the plant, causing it to collapse and ending with death. It will not be long before a characteristic rot of white color, with a watery texture. It is quite common to confuse these plant diseases with an attack of bacteria; the difference is that in this case, it will not smell bad, unlike what would happen if there were bacteria.

It usually occurs in those leaves, stems, and fruits with a size of up to 1.5m above the height of the soil.

Bacteria: Anthurium, Xanthomonas, Pseudomonas … just some of the bacteria that can attack plants. The symptoms that can produce the disease transmitted by these agents are very varied; the most normal thing is that there is rot that gives off a bad smell in certain areas.

The most effective way to avoid these attacks is with prevention techniques. The truth is that there are no bactericides that can be considered 100% effective. It also prevents injuries from occurring, since it will be the form of access that the bacteria will use to penetrate the plant organism.

Virus: Virtually any type of plant is capable of suffering the attack of viruses. The problem with these attacks is that the symptoms are so varied that they are difficult to diagnose. They are easy to confuse with other disorders or pathologies.

The most common symptoms are the presence of malformations and rolled sheets, yellowish pits ( mosaics ), abnormal growth.

It is important to keep in mind that plant viruses can rarely be cured, so we can only prevent them from occurring, and proliferate infecting other species.

Diseases of outdoor plants

The truth is that many diseases of indoor plants are also produced in outdoor plants. However, there are exclusive diseases or those that are more common in outdoor ones, such as the following:

Root rot, drowning and stem rots: These are considered to be the most harmful diseases for any plant. They usually occur in those soils that have limited porosity, or that are irrigated in excess. The fungi that cause this problem are usually the species Pythium, Phytophthora and Rhizoctonia, although there are also other fungi that can cause the same problem.

The plants that are attacked by them will present very varied symptomatology: the most common is that they have lesions at ground level, that collapse or wither. In the case of longer plants, these can become infected with pathogens that will cause decay in the highest part of them.

The affected areas usually have a brown color, and the tissue is rotten.

Powdery mildews: These plant diseases are characterized by a growth of white fungi on leaves, flowers, and stems. The vast majority of fungi can only attack a certain plant, but there is a certain number of fungi that can infect several types of plants.

The fungi survive thanks to the nutrients they obtain through the plants, but it avoids that the latter can absorb them. The development of the disease will be favored by high relative humidity.

The first thing that should be done in this case is to reduce the humidity of the environment, and then remove those affected leaves and stems before the disease can proliferate.

Leaf spots: Leaf spots are common in the landscape of any garden. In most cases, the presence of these spots does not represent a serious problem … but it is not always the case. In the case that it was caused by the fungus Entomosporium, the problem will be much more serious than it seems.

The spots produced by this symptom are very varied, ranging from very small to large areas. They usually have a red, purple or even brown tone.

Pathogens are able to survive on remains of leaves or stems; at the moment when there is rain or wind, they will disperse throughout the garden, infecting other organisms.

In the same way, as in most diseases of garden plants produced by fungi, the situation will get much worse if the humidity is high.

Leaf rusts: The rusts leaf is a rare plant disease that occurs only in certain species (eg lilacs, roses, or crabapples). The most common symptom of this disease is the presence of pustules that will appear on the leaves, capable of expanding spore characteristics of an orange-yellow color. You can also find yellow or orange spots on the underside of the leaves.

It is considered one of the diseases caused by excess water; it will be necessary to avoid that the leaves remain too humid. With the use of preventive fungicides, we can end this disease.

Leaf/flower galls: This disease is caused by the fungus Exobasidium spp. It is much more common when spring arrives, in cool and humid periods.

Its symptoms are the following: the tissues of the flowers and leaves will begin to swell until they become discolored and fleshy. The gills will end up becoming light green-pink. By the time they mature, the gills will turn light white.

The spores, with which the fungus will infect the rest of the plants, will be ready to disperse before the next season.

In addition to an unpleasant color, this plant disease will not cause more serious damage.

Blight by Botrytis: If you are looking for photos of plant diseases, you will notice that this results from the most chaotic. The deep will affect the stems and the crowns, being able to produce gangrene or wilting. In addition, it will cause the discoloration of the leaves and even the death of the plant.

The fungus will move through the water streams and by simply splashing water. They can also be moved by the help of insects.

The easiest way to detect these diseases from the plants of the garden or garden is by the presence of gray-brown spore masses on the walls of the plant tissues.

Fireblight: The Fire blight is another disease considered the most destructive to plants. The disease-causing microorganisms like this are the bacteria Erwinia amylovora. It usually affects the plants belonging to the Rosaceae family, such as apples, pears, fontina, pyracantha, quince, etc.

The twigs that emerge from the central stem will die, giving the appearance of how they would have burned. The fruits and leaves that are attached to the branch will also die. The most normal thing is that the fungus infects in the months between April-June, which is when the conditions are wetter and warmer.

Cannabis: And we end with this disease that is usually more common in cypress plants that have experienced problems of lack of water for a long time. The fungus that causes Canker or Gangrene is Seiridium unicorn.

The old foliage will start to die (both branches, twigs). Gangrene elongated with a marked reddish color will begin to appear. The bark will turn dark and will produce excess resin. The infection can occur anywhere on the tree or plant, at any stage of growth.

How to prevent plant diseases?

Preventive methods

To avoid diseases in indoor or outdoor plants, the best we can do is follow some preventive guidelines. If, however, the infection occurred, we can move on to the next section. Although we do not assure the plant’s cure.

Quality plants: The first thing you should do is to buy quality plants. The roots must be good and not be congested. The stems should be vigorous, lush … It is important to analyze the plants to determine if they have any kind of disease, injury or infection. If so, do not buy them.

Climatology: Choose plants according to the climate in which you are going to plant them. Choosing a plant in an inappropriate climate will leave you at the mercy of many diseases that could quickly end your life. For example, imagine that you want to plant the Kentia palm tree in cold weather. At the moment when a frost is present. It will be very weak, and it will be easier for it to succumb to the action of a plague. You should know that native species are more resistant to pests and diseases than exotic plants.

Characteristics of the soil: You must also know the type of soil you have in the garden. If it is too humid, fungi can appear more easily. If you have too much lime the dreaded iron chlorosis may appear because you do not have the right iron.

Resistant varieties: New varieties of flowers and vegetables appear on the market that has been modified to be resistant to fungi, viruses, and bacteria. Although they will not be 100% protected, it is worth opting for them.

Plantation: To avoid diseases of the plants it is important to select a good place of planting. Protect them from extreme environmental conditions (such as extreme wind, direct sunlight, frost, etc.).

Maintenance: If you are not going to have a lot of time to maintain them. Then choose a plant that practically stays alone. For example, those that do not need a lot of water to survive.

Eradication: If a fungus has killed a plant, infecting its roots and substrate. You can not plant again in the same place. If you do not have another, be sure to discard any remainder of the infected plant. In addition to changing the substrate.

Water only what is necessary: It is just as bad to water in excess, to irrigate very little. An excessive risk encourages the proliferation of fungi ( diseases caused by excess water are the most common), leading to root rot. At the same time, they can get used to the excess of irrigation badly. If they have too much water and do not rot for it. They could have a really bad time in case of a dry season.

Study water quality: Water quality can be the difference between achieving vigorous plant growth or dying prematurely. For example, as we have already commented, if the water has a lot of lime it is possible that there is a lack of iron. Water with a high pH can be too citrus for certain species.

Be careful to wet the leaves and flowers with watering, as this could encourage the development of diseases. At the same time, as we have already seen, there are many fungi that are able to travel from one plant to another simply by splashing (usual diseases of the leaves of plants ). If a plant is in poor condition. But we are going to try to save it, extreme precautions must be taken to prevent others from being infected.

How to cure plants and diseases?

In order to cure diseases of the garden plants. It will first be necessary to identify which pest or disease is affected. Next, it will be necessary to evaluate if it is worth treating it or not.

We have two large groups of products to act against these infections:

Chemical products: Here we have from insecticides, acaricides, nematicides, fungicides, soil disinfectants, topicides, rodenticides, etc.

Ecological products: Products that respect the environment and the plant. In this group, we have, for example, potash soap, mineral oils, rotenone, azadirachtin, pyrethrins, prepared with a base of plants and plant essences, biological insecticides, etc.


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