Blister smut. Bubble smut

The causative agent of the disease is Ustilago zeae.

Taxonomy. Class — Basidiomycetes; order —Ustilaginales

In Ukraine, corn smut is widespread, especially in areas with arid climates, where teliospores remain viable for a long time, and plants weakened by moisture deficiency are most susceptible to infection. All above-ground parts of plants are affected: leaves, stems, cobs, panicles, aerial roots.

Damage to corn smut occurs throughout the entire growing season (until the stage of milky-waxy ripeness of the grain); young organs that are growing are infected. In the affected areas, light green, slightly swollen spots first appear, which gradually grow and turn into swelling in the form of bubbles of different sizes and configurations. At first they are light in color, covered with a white, pink or red shell and filled with a grayish-white mucous mass, which later turns into a black-olive mass of teliospores.

As the teliospores mature, the membrane of the bubbles ruptures, and the teliospores are released with the help of wind, insects, etc. fall on healthy plants. At 98 - 100% relative humidity, they germinate and infection occurs. It is local in nature; blisters form where the pathogen enters. The incubation period for corn smut disease is 7-15 days. During the growing season of corn, the fungus forms several generations of teliospores, causing new plant lesions.

Main source of corn smut infection- teliospores on affected plant debris (especially in intact blisters), which remain viable for up to four years. They germinate with basidia, on which basidiospores are formed. The latter are capable of budding, forming sporidia (secondary conidia). Particularly intensive formation of sporidia occurs in soils rich in organic matter. Germination of teliospores in soil is observed already at a temperature of 8-10°C (optimal 25-30°C) and humidity 98-100%. Single teliospores quickly lose viability under the influence of moisture and saprophytic microorganisms.

Additional source of corn smut infection- spoiled seeds. The harmfulness of bladder smut is manifested in a sharp decrease in grain yield and green mass. When cobs are damaged, yield losses can reach 50-100%, vegetative organs - 25-50%.

Corn smut

Corn smut - Sorosporium reilianum photo

The causative agent of the disease is Sorosporium reilianum.

Taxonomy. Class - Basidiomycetes; order - Ustilaginales

Corn smut occurs in all soil and climatic zones of Ukraine, but is most common in the southern regions.

Affected plants are stunted, bushy, and ears do not form for a long time. The most characteristic symptoms of the disease appear on the generative organs. The cobs are completely destroyed, turning into a black oval-cone-shaped nodule with a spore mass and undestroyed wire bundles, covered on the outside with short wrappers; The panicle is completely or partially destroyed.

During the period of milky ripeness, teliospore grains are sprayed and fall into the soil and onto plants in large quantities. Some of them are retained behind the wrappers and spoil the grain during harvest.

The main source of corn head smut infection- teliospores in soil and on seeds. Their viability in the soil lasts up to two years.

Plant infection occurs in the soil during seed germination after emergence. The fungus is demanding at elevated temperatures, so the most intensive germination of teliospores and infection of seedlings occurs at a temperature of 28-30⁰C. The same temperature is optimal for the development of the disease during the growing season.

Protective measures against corn smut

Preventive protective measures:

optimal sowing time
compliance with crop rotation
seed dressing
high-quality soil treatment (incorporation of plant residues)

Chemical protection. Maxim XL is a combined fungicide to protect corn from fungal diseases spread by seeds and soil. The drug stimulates the germination of corn seeds, ensures maximum germination, has a beneficial effect on assimilation, improving the process of photosynthesis. Maxim XL is one of the most effective drugs against stem and root rot, molding of seeds caused by fungi of the genus Fusarium spp.,Pythium spp., Aspergillus spp., Penicillium spp.. During the growing season, the drug protects against dusty and blister smut.

Belongs to the higher fungi of the class Basidiomycetes, subclass Teliomycetes, order Golovnevye.

Cultures.

Affects corn.

Prevalence.

It is found in all regions of the Russian Federation where corn is cultivated.

Symptoms of the disease.

The disease affects corn throughout the growing season. It is characterized by the formation of whitish swellings and nodules of various sizes. On shoots and nodes it appears in the form of spherical-tuberous swellings with a diameter of up to 15 cm or more. On the leaves, swellings form along the veins and have an elongated shape. On the cobs, individual ovaries are affected, the development of which is delayed or stopped. They may also grow and take on an irregular shape. On sultanas, individual flowers are affected, which grow, forming blisters.

Biology of the pathogen.

At sites of infection, a pale or greenish-yellow swelling forms on all plant organs. Later, by the time the teliospores mature, the nodule darkens and is covered on top with a whitish-gray film that takes on a silvery sheen. Later, the nodule dries out, the covering film cracks and the released teliospores disperse, causing secondary infection. Some teliospores are retained in the affected ears of grain and in the field on post-harvest residues. Teliospores are able to germinate immediately as soon as they ripen, but in dry form they can persist for 5 years or longer. In natural humid conditions, they quickly lose their germination capacity, but, remaining in undisintegrated lumps in the field, they can serve as a source of primary infection for seedlings. Teliospores can also be introduced into the field with seed material. Teliospores, germinating, form basidia with basidiospores, which reproduce by budding. Sporidia sprout with growth tubes and penetrate only into young meristematic tissues. Haploid hyphae are formed from the germ tubes. The yield of green mass of corn due to disease is reduced by 25...50%, grain - by 50%.

Sources of infection.

Infected ears, plant residues, soil.

Preparations for protection.

Agrotechnical control measures.

Introduction to the production of resistant varieties, scientifically based seed production, compliance with crop rotation. Compliance with spatial isolation of seed plots from commercial crops, disinfection of agricultural machinery and equipment.

Ustilago zeae

Symptoms of corn smut:

Conditions for the development of corn smut:

Measures to combat corn smut:

optimal sowing time
compliance with crop rotation
seed dressing
high-quality soil tillage (incorporation of plant residues

LATIN NAME: Ustilago maydis (DC.) Corda

RUSSIAN NAME:

CHINESE NAME: Corn black fungus, corn black mold

TAXONOMIC POSITION:

Class: Basidiomycetes
Order: Ustilaginales
Family: Ustilaginaceae

MEDICINAL RAW MATERIALS: Sori

Morphological features

The corn black fungus is a sorus (group of fruiting bodies) 30-150 mm long. The sori form distinct, irregularly shaped, black-sooty galls that can be located in various parts of the host plant, although they are usually located on the cob. On the outside, young galls are covered with a layer of white leathery membrane, represented by mycelium mixed with plant tissue.

With age, the membrane acquires a purple-red color, and in mature fruiting bodies it becomes gray. After the sori mature, the membrane ruptures and releases a large amount of dark brown spore powder. Spores are spherical or ellipsoidal, rarely shapeless, 8-12 microns in diameter, the surface of the spores is finely warty, black-brown.

Ecology and distribution

The corn black fungus lives inside corn plants and forms large grayish-white growths on the surface of the cobs, stems, and sometimes leaves, inside which are black-brown powdery smut spores. Distributed in China in the provinces of Hebei, Shanxi, Heilongjiang, Liaoning, Jilin, Inner Mongolia, Anhui, Jiangsu, Zhejiang, Jiangxi, Fujian, Henan, Guangdong, Ningxia, etc. It is found in many countries of the world in corn-growing areas.

Nutritional and chemical composition

Poorly studied. The spores are highly poisonous. Research shows that corn black fungus contains many mineral components and is high in iron, calcium, magnesium, phosphorus, zinc and manganese. Contains ustilagin, sclerotic acid, trimethylalin. At the same time it includes 8 amino acids, of which the amino acid Cy (threonine) has the highest content. The corn black mushroom is considered by some peoples to be an edible and medicinal mushroom. The consumption of young corn black mushroom as food was practiced by the Mexican Indians. It is considered a very good seasoning in Mexican cuisine, and has recently attracted the attention of American chefs, and has a fairly high cost.

Pharmacological properties

1. Traditional application

Useful for the liver, spleen and stomach, gives good results for calming the spirit and neutralizing poisons. Corn smut spores are used in gynecology, and also as a blood purifier for eczema and scalp psoriasis. An alcohol tincture of crushed corn nodules with smut spores is used as a hemostatic agent.

The use of corn smut spores requires extreme caution.

2. Impact on the digestive system

Regular consumption of corn black fungus can prevent and treat stomach and intestinal ulcers, liver disease, and promotes intestinal function.

3. Biological role of microelements contained in corn black fungus

Microelements have very important physiological functions. Iron is part of hemoglobin, which is responsible for the transport of oxygen in the blood and is involved in hematopoiesis, being an activator of the synthesis of hemoproteins in the cell. Zinc affects the activity of more than 80 enzymes, is directly involved in the synthesis of polynucleotides and proteins and, therefore, affects cell division, growth and reproduction. Manganese is predominantly concentrated in the liver and spleen and is involved in the formation of certain enzymes, for example, in the formation of pyruvate decarboxylase. In addition, it is involved in sugar metabolism and plays an important role in the biosynthesis of nucleic acids.

4. The importance of amino acids contained in corn black fungus

Corn black fungus is rich in amino acids: threonine, isoleucine and tryptophan. Threonine, which is one of the essential amino acids, is characterized by a high content of zinc and manganese. It is involved in lipid metabolism, its absence can lead to fatty degeneration of the liver. Isoleucine is one of three branched chain amino acids. The ratio between branched and aromatic amino acids decreases from 3.0-3.5 in the body of a healthy person to 1.0-1.5 in people with liver pathology.

Therefore, isoleucine is used to treat liver diseases, participates in carbohydrate metabolism, and helps reduce blood cholesterol levels. Corn black fungus can also promote protein synthesis, which is why it is used as a support agent in the treatment of liver and kidney diseases. Tryptophan plays an important role in metabolism because it is transformed into serotonin, which is a substance that is a chemical transmitter of impulses between nerve cells in the brain and controls appetite, sleep, mood and emotions in humans.

5. Antitumor efficacy

The mushroom inhibits the growth of sarcoma 180 in mice.

Bibliography

Baomen, Lace'er. Modern trophology. Beijing: Chemical Industry, 2004.
Fanxuishen, Zhang Yingxin, Wansailan and others. Contents and functions of microelements // Study of microelements and health. 1999.16(1): 52.
Zhangbingsheng, Wanqingyuan. Analysis of trace elements in rheum essential oil // Study of trace elements and health. 1999, 16(1): 77.
Shanfeifen, Lihongmei, Wanshouli et al. Initial research on the fermentation of corn black fungus poliose // Product Science. 2002.23(11): 83.
Alexopoolus S. J. (translation by YaoYijian, Liyuzhu). Essays on mushroom science. Beijing: China Agriculture, 2006.

Symptoms of the disease in the form of bubble-like nodules (swells) of various sizes and shapes with a diameter of up to 15.0 cm or more are found on the stem, aerial roots, leaves, cobs, reproductive buds, panicles. Initially, the affected tissues lighten and grow into a mucous mass of a bluish-white hue. At the end of development, the nodules turn into a dusty mass of olive-black spores.

The disease affects plants at all stages of development during the growing season.

If the growth point is infected, the nodules grow linearly. In this case, it seems that the disease develops systemically.

The appearance of nodules on the stem leads to deformation and sometimes drying out of the entire plant as a whole. Stem damage is considered the most dangerous form of the disease.

After the formation of the fifth to eighth leaves, the infection appears on the leaf blades in the form of small nodules collected in groups.

Simultaneously with the ejection and the beginning of flowering of corn, the reproductive organs are affected. Sometimes they die completely.

Morphology

Teliospores are black-olive in mass, single ones are yellow-brown, spherical with a mesh pattern and fairly large setae, diameter 8-13 microns.

Basidiospores are unicellular, oblong, colorless. Size 3x1.2 microns.

The pathogen has many physiological races.

Biology

When the swellings mature, the mycelium disintegrates, forming a large number of teliospores.

The latter scatter and become the primary source of infection. The spores can only infect young, growing plant organs.

In the presence of dripping moisture, teliospores germinate within a few hours. The optimal germination temperature is between +23°C and +25°C. At a temperature of +12°C, spores lose their ability to germinate.

In spores that begin to germinate, after 15-20 hours a sprout is formed - a basidium, with rapidly forming basidiospores. They further reproduce by budding, producing many sporidia (secondary conidia).

Basidiospores and sporidia are able to withstand low humidity for 30-35 days.

The germ tube, formed during the germination of basidiospores and sporidia, sometimes directly from the basidia, is capable of penetrating into the plant only through the delicate epidermis of young meristematic tissues.

Haploid filamentous mycelium is formed from the germ tubes inside the plant tissues of corn. Its hyphae copulate and give rise to the formation of a diploid mycelium, the hyphae of which are thick and knotty. After 20-24 days, swellings are formed from the diploid mycelium, in which teliospores mature.

During the growing season, the mushroom produces three - four, and sometimes five generations. This leads to severe contamination of crops by the time the harvest begins.

Geographical distribution

Corn bunt is distributed throughout the world in areas where this crop is cultivated.

Maliciousness

Corn smut is one of the most harmful diseases. As a result of exposure to infection, young plants fall out and infertile ears are formed if they are infected early. Or a significant crop shortage due to damage to various above-ground organs.

The reduction in yield depends on the number and size of nodules on one plant.

The formation of large nodules reduces yield by 60% or more. In the presence of formations of medium size - by 25%, and in case of small sizes - by 10%.

It is noted that two swellings are three times more harmful than one.

Corn plants affected by the pathogen are not recommended for use as feed, either fresh or for ensiling, since the growths become toxic when teliospores form.