How mushrooms originated on earth - this question still has a number of hypotheses, none of which is the truth in the first instance. Some scientists suggest that fungi originated from primitive unicellular life forms - flagellates not containing chlorophyll, others are inclined to argue that the ancestors of fungi were various algae - for example, from a class of green algae, in which, for unknown reasons, chlorophyll was destroyed and they switched to saprophytic nutrition (extraction from the environment).
Fuligo Fuligo- a slimy fungus that lives on rotting stumps, noticeable in the second half of summer and autumn. Forms cushion-shaped nodules (they are called etalia) of a reddish or grayish color.
Lycogala- this slimy fungus lives in the hollows of stumps, on the bark, and forms pea-sized etalia of a reddish color, which later become gray.
Another dangerous mushroom of this class is unicellular Synchytrium endobiotocum which causes disease potato cancer. Potato cancer can be identified by the bumpy growths on the tubers. Potato cancer is a quarantine disease in many countries. It is believed that potato cancer was brought to us during the Second World War, as it appeared mainly in the western regions. The fight against this fungus is carried out by treating the soil with chloropicrin and other chemicals, as well as by working on the selection of new cancer-resistant varieties. Potato blight has become widespread in North America and Western Europe and causes significant damage every year.
Aspergillus- another marsupial fungus that causes a disease in plants called black mold Aspergillus niger. This disease is widespread for all types of plants, since fungi of this species reproduce very actively and intensively. Many species of Aspergillus are dangerous even to humans.
Phytopathogenic fungi are divided into three groups: necrotrophs, biotrophs and hemibiotrophs.
Necrotrophic mushrooms
Symptoms of diseases. which are caused by necrotrophic fungi, most often cause blackening ( necrosis) and death of the plant or its parts. Typically necrotrophs infect:
seedlings whose tissues have not yet developed strong covers that protect against infection: the roots and lower part of the stem (hypocotyledon) turn black (diseases are called root rot and “black leg”), mass death of seedlings is often observed;
Branches of woody plants damaged by frost: frost cracks and branches killed by frost are colonized by fungi, again due to the loss of immunity by dead cells; these fungi release toxins into the surrounding tissue, leading to cell death and expanding the infection zone;
vessels (tracheas) of the conducting system - xylem: in this case, the transport of water and soil nutrition elements is disrupted, so infected plants wilt even when growing in sufficiently moist soil; the disease is called Wilt or tracheomycosis;
Feeding on dead plant tissues has produced two properties, important for the development of plant protection systems against them:
- 1) indiscriminate choice of host plant ( broad phylogenetic specialization), due to which one type of fungus can infect many species of plants belonging to different botanical families;
- 2) the ability, after the death of the feeding plant, to return to the soil and feed on dead plant debris there.
The listed characteristics inherent in fungi characterize them as an ecological-trophic group, an ecomorph. Phylogenetically, fungi are representatives of several independent kingdoms. The differences between them are presented in table. 2.1.
Table 2.1
Characteristics of phylogenetically independent taxa, including fungi and fungi-like organisms
| Signs | Eumycetes | Oomycetes | Myxomycetes |
| Power type | Osmotrophic | Osmotrophic | Osmotrophic, zootrophic |
| Structural carbohydrates | Glucan (mannan), chitin | Glucan, cellulose | Cellulose, glucan |
| Storage carbohydrates | Glycogen, trehalose, sugar alcohols | Beta glucan (kelp) | Glycogen |
| Lysine synthesis | Via alpha amino adipate | Via diamino-pimelate | Via alpha amino adipate |
| Christa mitochondria | Ribbon-shaped | Tubular | Ribbon-shaped |
| Sexual process | Somatogamy, gametangiogamy | Oogamy | Somatogamy |
| Predominant type of thallus | Mycelium | Mycelium | Plasmodium pseudoplasmodium |
| Molecular phylogeny | Kingdom Mycobiontes | Kingdom Stramenopiles | Kingdom Myxobiontes |
| Predominant lifestyle | Ground | Water | Ground |
Plant diseases mean all causes that disrupt the correct conditions for their development. Diseases caused by these reasons can be divided into the following categories:
1) diseases caused by climatic and soil conditions;
2) diseases caused by animals;
3) diseases caused by plants.
Diseases caused by climatic and soil conditions
The first includes all violations of proper nutrition. They are caused by insufficient or excess humidity, warmth, light, dryness, and nutrients in the environment. This also includes diseases and damage caused by frost, drought and a number of different atmospheric phenomena (storms, hail, lightning).
For example, the consequence of a lack of water in the soil is short stature, stunting, and loss of leaves, ovaries, and fruits. Prolonged heat and drought cause spots on the leaves - “burns” and even complete drying. Direct exposure to sunlight can cause sunstroke - "paralysis", in which part or all of the plant withers almost instantly. At the same time, the lack of light causes weakening and abnormal stretching of the darkened parts. Excess bud moisture and lack of ventilation causes acidification of the soil, which has a very disastrous effect on the roots. Excess dampness in the soil causes flower buds to fall off, which is especially common in indoor crops. A lack of iron in the soil causes massive yellowing of the leaves. The lack of potassium in the soil often causes spotting on the leaves of some plants that love potassium fertilizer (buckwheat, potatoes). A lack of nutrients in the soil has a detrimental effect on plants. But an excess of nitrogenous substances often causes too vigorous growth of green parts to the detriment of fruiting. All the phenomena listed here in most cases are limited to single instances and do not have a mass character.
Diseases caused by animals
The second group includes all damage caused by animals, humans, and insects. The harm caused by the latter is especially significant due to their widespread nature. Various spiders, weevils, aphids, locusts, larvae, caterpillars, etc. Cause great harm to plants. They suck the juices out of them and destroy various organs, making their nests and shelters in them. All these pests, if they do not devour plants, then cause them to dry out and die off the parts they affect.
Diseases caused by plants
I would like to emphasize that no matter what painful phenomena plants deal with, they can always be classified into one of the three categories listed here. When starting to fight for any plant, you need to clearly understand what disease you are facing, and then carry out effective treatment. To do this, answer the following questions: when did the disease appear, what damage did it cause, how widespread is it, what signs does the disease express, compare affected and unaffected plant varieties, what soil do they grow on.
Cereals are perhaps the most common type of agricultural crop. In order to obtain large yields of such plants, they, like any others, of course, need to be looked after. When growing cereals, much attention is paid to the prevention of various types of fungal diseases. Infection with such infections significantly reduces yields and, consequently, causes huge losses to agricultural enterprises. Most often, cereals are infected with smut. This fungal disease can in some cases destroy the entire crop of wheat, rye or, for example, corn.
What causes
How do grain crops become infected with smut fungi?
Diseases caused by Basidiomycetes have remained a real mystery for researchers for a long time. Scientists first explained the blackening of the ear by a metabolic disorder inside the plants. Later, it was also suggested that such changes appear as a result of the vital activity of some insects or ciliates.
Researchers found spores of smut fungi in blackened plants only at the end of the 19th century. Since then, it has, of course, become easier to combat this disease of cereals.
How does mycelium develop?
Smut isThe disease is not only common, but also difficult to treat.A special feature of Basidiomycetes mushrooms is their very strong and viable mycelium. It usually spreads across the affected tissue between the cells, but sometimes it can penetrate through the cells.
Before breaking up into spores, the Basidiomycetes mycelium begins to branch very strongly. Its hyphae are divided by additional transverse partitions. After some time, the shells of the mycelial cells become slimy and then replaced with denser ones. Next, the cells are detached from the main branch of the mycelium. Such isolated areas are called smut spores. On the ear they form a clearly visible black mass (sometimes dense, sometimes dusty).
The mycelium of this type of mushroom usually does not penetrate the entire plant. Depending on the specific type of pathogen, it can be seen, for example, in the ovaries of crops, in the stem, in parts of the ear.
What types of smut are there?
stem;
vesicular;
hard;
dusty;
dwarf.
According to the nature of the manifestation oncerealsculturesSmut is divided into hard and dusty. In the first case, only the grains themselves are affected. Their shells are almost completely preserved. In them, like in bags, are the spores of the fungus.
When infected with dust smut, the plant is almost completely destroyed. The fungal spores do not linger on the ear. Gusts of wind very quickly carry them across the entire field.
What harm does a mushroom cause?
Flour from wheat, rye, etc., infected with smut, is of poor quality. At the manufacturing stage, infected grain must be additionally sifted to remove fungal spores. However, baked goods made from such flour still turn out tasteless. Unfortunately, the products acquire a characteristic smut taste.
How to fight
To prevent infection of grain crops with smut, you should:
be sure to treat the seeds before planting;
follow agricultural practices - alternate sowing grain with other agricultural crops.
You should also try to grow only resistant varieties of cereals in your fields. Breeders have bred many of these. Eg,It develops quite rarely on varieties such as Kinelskoe 92, Kharkovskoe 86, Saratovskoe 3, etc.
Treating is usually done by keeping the planting material in warm water (about 47 o C) for 3 hours. You can also kill smut spores with special drugs, for example, Vitavax.
As already mentioned, infection of cereal crops with this disease can also occur directly through the soil. In addition to alternating types of agricultural plants, measures such as peeling the soil in the spring should therefore be taken.
What damage can a disease cause to a summer resident?
In order to protect plants, in the garden, as well as in the fields of agricultural enterprises, you should first of all adhere to the rules of crop rotation. If this condition is met, the summer resident most likely will not have to face such a problem as corn smut.
Also, to reduce the risk of crop loss due to the fungus, it is worth using seed only from smut-resistant varieties and treating it with Triticonazole before planting. The corn bushes themselves need to be treated with some kind of fungicide from time to time for prevention. In autumn, all plant residues should be collected from the beds and burned. In this case, the soil itself on the site needs to be dug up using a spade bayonet.
